Merge tag '6.0' into HEAD

Bug: 86678

Change-Id: Ief079a765fc72fb108c51d4ca182105dac16d776
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
new file mode 100644
index 0000000..82bf0f0
--- /dev/null
+++ b/.github/workflows/ci.yaml
@@ -0,0 +1,432 @@
+---
+# This is the CI workflow (not the artifact build/release workflow). The workflows
+# are split because GHA doesn't support a dynamic/conditional matrix. This workflow
+# has slow jobs and jobs that require private GHA runners (eg, M1 Mac) commented out.defaults:
+# Ensure changes are synced with manual_artifact_build.yaml.
+name: PyYAML CI
+
+on:
+  push:
+  pull_request:
+    types: [opened, synchronize, edited, reopened]
+  workflow_dispatch:
+
+env:
+  LIBYAML_REPO: https://github.com/yaml/libyaml
+  LIBYAML_REF: 0.2.5
+
+jobs:
+  python_sdist:
+    name: pyyaml sdist
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout PyYAML
+      uses: actions/checkout@v2
+
+    - name: Install a python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.x
+
+    - name: Build sdist
+      env:
+        PYYAML_FORCE_CYTHON: 1
+        PYYAML_FORCE_LIBYAML: 0
+      run: |
+        python -V
+        python -m pip install build
+
+        python -m build .
+
+        # Ensure exactly one artifact was produced.
+        [[ $(shopt -s nullglob; ls dist/*.tar.gz | wc -w) == 1 ]] || {
+          echo "Unexpected content in dist dir: '$(ls dist/*.tar.gz)'."
+          exit 1
+        }
+
+    - name: Test sdist
+      run: |
+        # Install some libyaml headers.
+        # TODO Should we smoke test the sdist against the libyaml we built?
+        sudo apt update
+        sudo apt install libyaml-dev -y
+
+        # Ensure Cython is not present so we use only what's in the sdist.
+        python -m pip uninstall Cython -y || true
+
+        # Pass no extra args.
+        # We should auto-install with libyaml since it's present.
+        python -m pip install dist/*.tar.gz -v
+
+        python packaging/build/smoketest.py
+
+    - name: Upload sdist artifact
+      uses: actions/upload-artifact@v2
+      with:
+        name: dist
+        path: dist/*.tar.gz
+
+
+  linux_libyaml:
+    name: libyaml ${{matrix.cfg.arch}} ${{matrix.cfg.platform}}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        cfg:
+        - { platform: manylinux1, arch: x86_64 }
+        - { platform: manylinux2014, arch: x86_64 }
+#        - { platform: manylinux2014, arch: aarch64 }
+#        - { platform: manylinux2014, arch: s390x }
+    env:
+      DOCKER_IMAGE: quay.io/pypa/${{matrix.cfg.platform}}_${{matrix.cfg.arch}}
+    steps:
+    - name: Check cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_${{matrix.cfg.platform}}_${{matrix.cfg.arch}}_${{env.LIBYAML_REF}}
+
+    - name: configure docker foreign arch support
+      uses: docker/setup-qemu-action@v1
+      if: matrix.cfg.arch != 'x86_64' && steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Checkout pyyaml
+      uses: actions/checkout@v2
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Build libyaml
+      run: >
+        docker run --rm
+        --volume "$(pwd):/io"
+        --env LIBYAML_REF
+        --env LIBYAML_REPO
+        --workdir /io
+        "$DOCKER_IMAGE"
+        /io/packaging/build/libyaml.sh
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: ensure output is world readable (or cache fill fails with Permission Denied)
+      run: >
+        sudo chmod -R a+r ./libyaml/
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+
+  linux_pyyaml:
+    needs: linux_libyaml
+    name: pyyaml ${{matrix.arch}} ${{matrix.platform}} ${{matrix.spec}}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+        - { platform: manylinux1, arch: x86_64, spec: cp36 }
+#        - { platform: manylinux1, arch: x86_64, spec: cp37 }
+#        - { platform: manylinux1, arch: x86_64, spec: cp38 }
+#        - { platform: manylinux1, arch: x86_64, spec: cp39 }
+        - { platform: manylinux2014, arch: x86_64, spec: cp310 }
+#        - { platform: manylinux2014, arch: aarch64, spec: cp36 }
+#        - { platform: manylinux2014, arch: aarch64, spec: cp37 }
+#        - { platform: manylinux2014, arch: aarch64, spec: cp38 }
+#        - { platform: manylinux2014, arch: aarch64, spec: cp39 }
+#        - { platform: manylinux2014, arch: aarch64, spec: cp310 }
+#        - { platform: manylinux2014, arch: s390x, spec: cp36 }
+#        - { platform: manylinux2014, arch: s390x, spec: cp37 }
+#        - { platform: manylinux2014, arch: s390x, spec: cp38 }
+#        - { platform: manylinux2014, arch: s390x, spec: cp39 }
+#        - { platform: manylinux2014, arch: s390x, spec: cp310 }
+
+    steps:
+    - name: Checkout PyYAML
+      uses: actions/checkout@v2
+
+    - name: Fetch cached libyaml
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_${{matrix.platform}}_${{matrix.arch}}_${{env.LIBYAML_REF}}
+
+    - name: Ensure libyaml fetched
+      run: exit 1
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: configure docker foreign arch support
+      uses: docker/setup-qemu-action@v1
+      if: matrix.arch != 'x86_64'
+
+    - name: Build/Test/Package
+      env:
+        CIBW_ARCHS: all
+        CIBW_BUILD: ${{matrix.spec}}-manylinux_${{matrix.arch}}
+        CIBW_BUILD_VERBOSITY: 1
+        # containerized Linux builds require explicit CIBW_ENVIRONMENT
+        CIBW_ENVIRONMENT: >
+          C_INCLUDE_PATH=libyaml/include
+          LIBRARY_PATH=libyaml/src/.libs
+          LD_LIBRARY_PATH=libyaml/src/.libs
+          PYYAML_FORCE_CYTHON=1
+          PYYAML_FORCE_LIBYAML=1
+        CIBW_TEST_COMMAND: cd {project}; python tests/lib/test_all.py
+      run: |
+        set -eux
+        python3 -V
+        python3 -m pip install -U --user cibuildwheel
+        python3 -m cibuildwheel --platform auto --output-dir dist .
+
+    - name: Upload artifacts
+      uses: actions/upload-artifact@v2
+      with:
+        name: dist
+        path: dist/*.whl
+        if-no-files-found: error
+
+  macos_libyaml:
+    name: libyaml macos ${{matrix.arch}}
+    strategy:
+      matrix:
+        include:
+        - arch: x86_64
+#        - arch: arm64
+#          runs_on: [self-hosted, macOS, arm64]
+#          deployment_target: '11.0'
+#          run_wrapper: arch -arm64 bash --noprofile --norc -eo pipefail {0}
+#          sdkroot: macosx11.3
+    defaults:
+      run:
+        shell: ${{ matrix.run_wrapper || 'bash --noprofile --norc -eo pipefail {0}' }}
+    runs-on: ${{ matrix.runs_on || 'macos-10.15' }}
+    steps:
+    - name: Check cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_macos_${{matrix.arch}}_${{env.LIBYAML_REF}}
+
+    - name: Checkout PyYAML
+      uses: actions/checkout@v2
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Build libyaml
+      env:
+        MACOSX_DEPLOYMENT_TARGET: ${{ matrix.deployment_target || '10.9' }}
+        SDKROOT: ${{ matrix.sdkroot || 'macosx' }}
+      run: |
+        set -eux
+        brew install automake coreutils m4
+        bash ./packaging/build/libyaml.sh
+        echo "finished artifact arch is $(lipo -archs libyaml/src/.libs/libyaml.a)"
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+
+  macos_pyyaml:
+    needs: macos_libyaml
+    name: pyyaml ${{ matrix.spec }}
+    runs-on: ${{ matrix.runs_on || 'macos-10.15' }}
+    defaults:
+      run:
+        shell: ${{ matrix.run_wrapper || 'bash --noprofile --norc -eo pipefail {0}' }}
+    strategy:
+      matrix:
+        include:
+        - spec: cp36-macosx_x86_64
+#        - spec: cp37-macosx_x86_64
+#        - spec: cp38-macosx_x86_64
+#        - spec: cp39-macosx_x86_64
+        - spec: cp310-macosx_x86_64
+
+#        # build for arm64 under a hacked macOS 12 self-hosted x86_64-on-arm64 runner until arm64 is fully supported
+#        # FIXME: ? cp38-macosx_arm64 requires special handling and fails some test_zdist tests under cibw 2.1.2, skip it (so Apple's XCode python3 won't have a wheel)
+#        - spec: cp39-macosx_arm64
+#          deployment_target: '11.0'
+#          runs_on: [self-hosted, macOS, arm64]
+#          arch: arm64
+#          run_wrapper: arch -arm64 bash --noprofile --norc -eo pipefail {0}
+#          sdkroot: macosx11.3
+#
+#        - spec: cp310-macosx_arm64
+#          deployment_target: '11.0'
+#          runs_on: [self-hosted, macOS, arm64]
+#          arch: arm64
+#          run_wrapper: arch -arm64 bash --noprofile --norc -eo pipefail {0}
+#          sdkroot: macosx11.3
+
+    steps:
+    - name: Checkout PyYAML
+      uses: actions/checkout@v2
+
+    - name: Get cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_macos_${{ matrix.arch || 'x86_64' }}_${{env.LIBYAML_REF}}
+
+    - name: Ensure libyaml fetched
+      run: exit 1
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Build/Test/Package
+      env:
+        C_INCLUDE_PATH: libyaml/include
+        CIBW_BUILD: ${{matrix.spec}}
+        CIBW_BUILD_VERBOSITY: 1
+        CIBW_TEST_COMMAND: cd {project}; python tests/lib/test_all.py
+        LIBRARY_PATH: libyaml/src/.libs
+        MACOSX_DEPLOYMENT_TARGET: ${{ matrix.deployment_target || '10.9' }}
+        SDKROOT: ${{ matrix.sdkroot || 'macosx' }}
+      run: |
+        python3 -V
+        python3 -m pip install -U --user cibuildwheel
+        python3 -m cibuildwheel --platform auto --output-dir dist .
+
+    - name: Upload artifacts
+      uses: actions/upload-artifact@v2
+      with:
+        name: dist
+        path: dist/*.whl
+        if-no-files-found: error
+
+  windows_libyaml:
+    name: libyaml ${{matrix.platform}} ${{matrix.arch}}
+    runs-on: ${{matrix.platform}}
+    strategy:
+      matrix:
+        include:
+        - platform: windows-2016
+          arch: x64
+        - platform: windows-2016
+          arch: win32
+    steps:
+    - name: Get cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_${{matrix.platform}}_${{matrix.arch}}_${{env.LIBYAML_REF}}
+
+    - name: Build libyaml
+      shell: bash
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+      run: |
+        # git spews all over stderr unless we tell it not to
+        export GIT_REDIRECT_STDERR="2>&1"
+
+        if [[ ! -d ./libyaml ]]; then
+          git clone -b ${{ env.LIBYAML_REF }} ${{ env.LIBYAML_REPO }} 2>&1
+        fi
+
+        pushd libyaml
+        git clean -fdx
+        popd
+
+        mkdir libyaml/build
+
+        pushd libyaml/build
+        cmake.exe -G "Visual Studio 15 2017" -A ${{ matrix.arch }} -DYAML_STATIC_LIB_NAME=yaml ..
+        cmake.exe --build . --config Release
+        popd
+
+
+  windows_pyyaml:
+    needs: windows_libyaml
+    name: pyyaml ${{ matrix.platform }} ${{matrix.python_arch}} ${{matrix.spec}}
+    runs-on: ${{matrix.platform}}
+    strategy:
+      matrix:
+        include:
+        - platform: windows-2016
+          build_arch: x64
+          python_arch: x64
+          spec: 3.6
+#        - platform: windows-2016
+#          build_arch: x64
+#          python_arch: x64
+#          spec: 3.7
+#        - platform: windows-2016
+#          build_arch: x64
+#          python_arch: x64
+#          spec: 3.8
+#        - platform: windows-2016
+#          build_arch: x64
+#          python_arch: x64
+#          spec: 3.9
+        - platform: windows-2016
+          build_arch: x64
+          python_arch: x64
+          spec: '3.10'
+        - platform: windows-2016
+          build_arch: win32
+          python_arch: x86
+          spec: 3.6
+#        - platform: windows-2016
+#          build_arch: win32
+#          python_arch: x86
+#          spec: 3.7
+#        - platform: windows-2016
+#          build_arch: win32
+#          python_arch: x86
+#          spec: 3.8
+#        - platform: windows-2016
+#          build_arch: win32
+#          python_arch: x86
+#          spec: 3.9
+        - platform: windows-2016
+          build_arch: win32
+          python_arch: x86
+          spec: '3.10'
+    steps:
+    # autocrlf screws up tests under Windows
+    - name: Set git to use LF
+      run: |
+        git config --global core.autocrlf false
+        git config --global core.eol lf
+
+    - name: Checkout pyyaml
+      uses: actions/checkout@v2
+
+    - name: Get cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_${{matrix.platform}}_${{matrix.build_arch}}_${{env.LIBYAML_REF}}
+
+    - name: Ensure libyaml fetched
+      run: exit 1
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Install python ${{ matrix.spec }}
+      uses: actions/setup-python@v2
+      with:
+        architecture: ${{ matrix.python_arch }}
+        python-version: ${{ matrix.spec }}
+
+    - name: Build/Test/Package
+      env:
+        PYYAML_FORCE_CYTHON: 1
+        PYYAML_FORCE_LIBYAML: 1
+      shell: bash
+      run: |
+        set -eux
+        python -V
+        python -m pip install Cython wheel
+
+        python setup.py \
+        --with-libyaml build_ext \
+        -I libyaml/include \
+        -L libyaml/build/Release \
+        -D YAML_DECLARE_STATIC \
+        build bdist_wheel
+
+        # run tests on built wheel
+        python -m pip install dist/*.whl
+        python tests/lib/test_all.py
+
+    - name: Upload artifacts
+      uses: actions/upload-artifact@v2
+      with:
+        name: dist
+        path: dist/*.whl
+        if-no-files-found: error
+...
diff --git a/.github/workflows/manual_artifact_build.yaml b/.github/workflows/manual_artifact_build.yaml
new file mode 100644
index 0000000..519276e
--- /dev/null
+++ b/.github/workflows/manual_artifact_build.yaml
@@ -0,0 +1,430 @@
+---
+# This is the actual artifact build/release workflow. This workflow exists temporarily
+# because GHA doesn't support a dynamic/conditional matrix. Ensure changes are synced with ci.yaml.
+name: Manual Artifact Build
+
+on:
+#  push:
+#  pull_request:
+#    types: [opened, synchronize, edited, reopened]
+  workflow_dispatch:
+
+env:
+  LIBYAML_REPO: https://github.com/yaml/libyaml
+  LIBYAML_REF: 0.2.5
+
+jobs:
+  python_sdist:
+    name: pyyaml sdist
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout PyYAML
+      uses: actions/checkout@v2
+
+    - name: Install a python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.x
+
+    - name: Build sdist
+      env:
+        PYYAML_FORCE_CYTHON: 1
+        PYYAML_FORCE_LIBYAML: 0
+      run: |
+        python -V
+        python -m pip install build
+
+        python -m build .
+
+        # Ensure exactly one artifact was produced.
+        [[ $(shopt -s nullglob; ls dist/*.tar.gz | wc -w) == 1 ]] || {
+          echo "Unexpected content in dist dir: '$(ls dist/*.tar.gz)'."
+          exit 1
+        }
+
+    - name: Test sdist
+      run: |
+        # Install some libyaml headers.
+        # TODO Should we smoke test the sdist against the libyaml we built?
+        sudo apt update
+        sudo apt install libyaml-dev -y
+
+        # Ensure Cython is not present so we use only what's in the sdist.
+        python -m pip uninstall Cython -y || true
+
+        # Pass no extra args.
+        # We should auto-install with libyaml since it's present.
+        python -m pip install dist/*.tar.gz -v
+
+        python packaging/build/smoketest.py
+
+    - name: Upload sdist artifact
+      uses: actions/upload-artifact@v2
+      with:
+        name: dist
+        path: dist/*.tar.gz
+
+
+  linux_libyaml:
+    name: libyaml ${{matrix.cfg.arch}} ${{matrix.cfg.platform}}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        cfg:
+        - { platform: manylinux1, arch: x86_64 }
+        - { platform: manylinux2014, arch: x86_64 }
+        - { platform: manylinux2014, arch: aarch64 }
+        - { platform: manylinux2014, arch: s390x }
+    env:
+      DOCKER_IMAGE: quay.io/pypa/${{matrix.cfg.platform}}_${{matrix.cfg.arch}}
+    steps:
+    - name: Check cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_${{matrix.cfg.platform}}_${{matrix.cfg.arch}}_${{env.LIBYAML_REF}}
+
+    - name: configure docker foreign arch support
+      uses: docker/setup-qemu-action@v1
+      if: matrix.cfg.arch != 'x86_64' && steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Checkout pyyaml
+      uses: actions/checkout@v2
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Build libyaml
+      run: >
+        docker run --rm
+        --volume "$(pwd):/io"
+        --env LIBYAML_REF
+        --env LIBYAML_REPO
+        --workdir /io
+        "$DOCKER_IMAGE"
+        /io/packaging/build/libyaml.sh
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: ensure output is world readable (or cache fill fails with Permission Denied)
+      run: >
+        sudo chmod -R a+r ./libyaml/
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+
+  linux_pyyaml:
+    needs: linux_libyaml
+    name: pyyaml ${{matrix.arch}} ${{matrix.platform}} ${{matrix.spec}}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        include:
+        - { platform: manylinux1, arch: x86_64, spec: cp36 }
+        - { platform: manylinux1, arch: x86_64, spec: cp37 }
+        - { platform: manylinux1, arch: x86_64, spec: cp38 }
+        - { platform: manylinux1, arch: x86_64, spec: cp39 }
+        - { platform: manylinux2014, arch: x86_64, spec: cp310 }
+        - { platform: manylinux2014, arch: aarch64, spec: cp36 }
+        - { platform: manylinux2014, arch: aarch64, spec: cp37 }
+        - { platform: manylinux2014, arch: aarch64, spec: cp38 }
+        - { platform: manylinux2014, arch: aarch64, spec: cp39 }
+        - { platform: manylinux2014, arch: aarch64, spec: cp310 }
+        - { platform: manylinux2014, arch: s390x, spec: cp36 }
+        - { platform: manylinux2014, arch: s390x, spec: cp37 }
+        - { platform: manylinux2014, arch: s390x, spec: cp38 }
+        - { platform: manylinux2014, arch: s390x, spec: cp39 }
+        - { platform: manylinux2014, arch: s390x, spec: cp310 }
+
+    steps:
+    - name: Checkout PyYAML
+      uses: actions/checkout@v2
+
+    - name: Fetch cached libyaml
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_${{matrix.platform}}_${{matrix.arch}}_${{env.LIBYAML_REF}}
+
+    - name: Ensure libyaml fetched
+      run: exit 1
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: configure docker foreign arch support
+      uses: docker/setup-qemu-action@v1
+      if: matrix.arch != 'x86_64'
+
+    - name: Build/Test/Package
+      env:
+        CIBW_ARCHS: all
+        CIBW_BUILD: ${{matrix.spec}}-manylinux_${{matrix.arch}}
+        CIBW_BUILD_VERBOSITY: 1
+        # containerized Linux builds require explicit CIBW_ENVIRONMENT
+        CIBW_ENVIRONMENT: >
+          C_INCLUDE_PATH=libyaml/include
+          LIBRARY_PATH=libyaml/src/.libs
+          LD_LIBRARY_PATH=libyaml/src/.libs
+          PYYAML_FORCE_CYTHON=1
+          PYYAML_FORCE_LIBYAML=1
+        CIBW_TEST_COMMAND: cd {project}; python tests/lib/test_all.py
+      run: |
+        set -eux
+        python3 -V
+        python3 -m pip install -U --user cibuildwheel
+        python3 -m cibuildwheel --platform auto --output-dir dist .
+
+    - name: Upload artifacts
+      uses: actions/upload-artifact@v2
+      with:
+        name: dist
+        path: dist/*.whl
+        if-no-files-found: error
+
+  macos_libyaml:
+    name: libyaml macos ${{matrix.arch}}
+    strategy:
+      matrix:
+        include:
+        - arch: x86_64
+        - arch: arm64
+          runs_on: [self-hosted, macOS, arm64]
+          deployment_target: '11.0'
+          run_wrapper: arch -arm64 bash --noprofile --norc -eo pipefail {0}
+          sdkroot: macosx11.3
+    defaults:
+      run:
+        shell: ${{ matrix.run_wrapper || 'bash --noprofile --norc -eo pipefail {0}' }}
+    runs-on: ${{ matrix.runs_on || 'macos-10.15' }}
+    steps:
+    - name: Check cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_macos_${{matrix.arch}}_${{env.LIBYAML_REF}}
+
+    - name: Checkout PyYAML
+      uses: actions/checkout@v2
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Build libyaml
+      env:
+        MACOSX_DEPLOYMENT_TARGET: ${{ matrix.deployment_target || '10.9' }}
+        SDKROOT: ${{ matrix.sdkroot || 'macosx' }}
+      run: |
+        set -eux
+        brew install automake coreutils m4
+        bash ./packaging/build/libyaml.sh
+        echo "finished artifact arch is $(lipo -archs libyaml/src/.libs/libyaml.a)"
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+
+  macos_pyyaml:
+    needs: macos_libyaml
+    name: pyyaml ${{ matrix.spec }}
+    runs-on: ${{ matrix.runs_on || 'macos-10.15' }}
+    defaults:
+      run:
+        shell: ${{ matrix.run_wrapper || 'bash --noprofile --norc -eo pipefail {0}' }}
+    strategy:
+      matrix:
+        include:
+        - spec: cp36-macosx_x86_64
+        - spec: cp37-macosx_x86_64
+        - spec: cp38-macosx_x86_64
+        - spec: cp39-macosx_x86_64
+        - spec: cp310-macosx_x86_64
+
+        # build for arm64 under a hacked macOS 12 self-hosted x86_64-on-arm64 runner until arm64 is fully supported
+        # FIXME: ? cp38-macosx_arm64 requires special handling and fails some test_zdist tests under cibw 2.1.2, skip it (so Apple's XCode python3 won't have a wheel)
+        - spec: cp39-macosx_arm64
+          deployment_target: '11.0'
+          runs_on: [self-hosted, macOS, arm64]
+          arch: arm64
+          run_wrapper: arch -arm64 bash --noprofile --norc -eo pipefail {0}
+          sdkroot: macosx11.3
+
+        - spec: cp310-macosx_arm64
+          deployment_target: '11.0'
+          runs_on: [self-hosted, macOS, arm64]
+          arch: arm64
+          run_wrapper: arch -arm64 bash --noprofile --norc -eo pipefail {0}
+          sdkroot: macosx11.3
+
+    steps:
+    - name: Checkout PyYAML
+      uses: actions/checkout@v2
+
+    - name: Get cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_macos_${{ matrix.arch || 'x86_64' }}_${{env.LIBYAML_REF}}
+
+    - name: Ensure libyaml fetched
+      run: exit 1
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Build/Test/Package
+      env:
+        C_INCLUDE_PATH: libyaml/include
+        CIBW_BUILD: ${{matrix.spec}}
+        CIBW_BUILD_VERBOSITY: 1
+        CIBW_TEST_COMMAND: cd {project}; python tests/lib/test_all.py
+        LIBRARY_PATH: libyaml/src/.libs
+        MACOSX_DEPLOYMENT_TARGET: ${{ matrix.deployment_target || '10.9' }}
+        SDKROOT: ${{ matrix.sdkroot || 'macosx' }}
+      run: |
+        python3 -V
+        python3 -m pip install -U --user cibuildwheel
+        python3 -m cibuildwheel --platform auto --output-dir dist .
+
+    - name: Upload artifacts
+      uses: actions/upload-artifact@v2
+      with:
+        name: dist
+        path: dist/*.whl
+        if-no-files-found: error
+
+  windows_libyaml:
+    name: libyaml ${{matrix.platform}} ${{matrix.arch}}
+    runs-on: ${{matrix.platform}}
+    strategy:
+      matrix:
+        include:
+        - platform: windows-2016
+          arch: x64
+        - platform: windows-2016
+          arch: win32
+    steps:
+    - name: Get cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_${{matrix.platform}}_${{matrix.arch}}_${{env.LIBYAML_REF}}
+
+    - name: Build libyaml
+      shell: bash
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+      run: |
+        # git spews all over stderr unless we tell it not to
+        export GIT_REDIRECT_STDERR="2>&1"
+
+        if [[ ! -d ./libyaml ]]; then
+          git clone -b ${{ env.LIBYAML_REF }} ${{ env.LIBYAML_REPO }} 2>&1
+        fi
+
+        pushd libyaml
+        git clean -fdx
+        popd
+
+        mkdir libyaml/build
+
+        pushd libyaml/build
+        cmake.exe -G "Visual Studio 15 2017" -A ${{ matrix.arch }} -DYAML_STATIC_LIB_NAME=yaml ..
+        cmake.exe --build . --config Release
+        popd
+
+
+  windows_pyyaml:
+    needs: windows_libyaml
+    name: pyyaml ${{ matrix.platform }} ${{matrix.python_arch}} ${{matrix.spec}}
+    runs-on: ${{matrix.platform}}
+    strategy:
+      matrix:
+        include:
+        - platform: windows-2016
+          build_arch: x64
+          python_arch: x64
+          spec: 3.6
+        - platform: windows-2016
+          build_arch: x64
+          python_arch: x64
+          spec: 3.7
+        - platform: windows-2016
+          build_arch: x64
+          python_arch: x64
+          spec: 3.8
+        - platform: windows-2016
+          build_arch: x64
+          python_arch: x64
+          spec: 3.9
+        - platform: windows-2016
+          build_arch: x64
+          python_arch: x64
+          spec: '3.10'
+        - platform: windows-2016
+          build_arch: win32
+          python_arch: x86
+          spec: 3.6
+        - platform: windows-2016
+          build_arch: win32
+          python_arch: x86
+          spec: 3.7
+        - platform: windows-2016
+          build_arch: win32
+          python_arch: x86
+          spec: 3.8
+        - platform: windows-2016
+          build_arch: win32
+          python_arch: x86
+          spec: 3.9
+        - platform: windows-2016
+          build_arch: win32
+          python_arch: x86
+          spec: '3.10'
+    steps:
+    # autocrlf screws up tests under Windows
+    - name: Set git to use LF
+      run: |
+        git config --global core.autocrlf false
+        git config --global core.eol lf
+
+    - name: Checkout pyyaml
+      uses: actions/checkout@v2
+
+    - name: Get cached libyaml state
+      id: cached_libyaml
+      uses: actions/cache@v2
+      with:
+        path: libyaml
+        key: libyaml_${{matrix.platform}}_${{matrix.build_arch}}_${{env.LIBYAML_REF}}
+
+    - name: Ensure libyaml fetched
+      run: exit 1
+      if: steps.cached_libyaml.outputs.cache-hit != 'true'
+
+    - name: Install python ${{ matrix.spec }}
+      uses: actions/setup-python@v2
+      with:
+        architecture: ${{ matrix.python_arch }}
+        python-version: ${{ matrix.spec }}
+
+    - name: Build/Test/Package
+      env:
+        PYYAML_FORCE_CYTHON: 1
+        PYYAML_FORCE_LIBYAML: 1
+      shell: bash
+      run: |
+        set -eux
+        python -V
+        python -m pip install Cython wheel
+
+        python setup.py \
+        --with-libyaml build_ext \
+        -I libyaml/include \
+        -L libyaml/build/Release \
+        -D YAML_DECLARE_STATIC \
+        build bdist_wheel
+
+        # run tests on built wheel
+        python -m pip install dist/*.whl
+        python tests/lib/test_all.py
+
+    - name: Upload artifacts
+      uses: actions/upload-artifact@v2
+      with:
+        name: dist
+        path: dist/*.whl
+        if-no-files-found: error
+...
diff --git a/.gitignore b/.gitignore
index 9915308..e531e48 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,10 +1,19 @@
-# This file is generated by Cython
-ext/_yaml.c
-
-# Tox and Build Artifacts
-.tox/
+# build outputs
+/dist/*
+/build/*
+/lib/PyYAML.egg-info/*
+/wheelhouse/*
+/yaml/_yaml.c
 MANIFEST
-build/
+**/*.so
+**/*.dylib
+**/*.pyd
 
-# Python runtime Artifacts
-*.pyc
+
+# cached Python binaries
+*.py[cdo]
+_pycache_/*
+
+# local IDE state
+/.idea/*
+
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index c01b079..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,26 +0,0 @@
-language: python
-
-sudo: false
-
-cache: pip
-
-matrix:
-  include:
-    - python: 2.6
-      env: TOXENV=py26
-    - python: 2.7
-      env: TOXENV=py27
-    - python: 3.3
-      env: TOXENV=py33
-    - python: 3.4
-      env: TOXENV=py34
-    - python: 3.5
-      env: TOXENV=py35
-    - python: 3.6
-      env: TOXENV=py36
-    - python: pypy
-      env: TOXENV=pypy
-
-install: pip install tox
-
-script: tox
diff --git a/CHANGES b/CHANGES
index 141e115..c37d9be 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,118 @@
 
-For a complete Mercurial changelog, see
-'https://bitbucket.org/xi/pyyaml/commits'.
+For a complete changelog, see:
+
+* https://github.com/yaml/pyyaml/commits/
+* https://bitbucket.org/xi/pyyaml/commits/
+
+6.0 (2021-10-13)
+
+* https://github.com/yaml/pyyaml/pull/327 -- Change README format to Markdown
+* https://github.com/yaml/pyyaml/pull/483 -- Add a test for YAML 1.1 types
+* https://github.com/yaml/pyyaml/pull/497 -- fix float resolver to ignore `.` and `._`
+* https://github.com/yaml/pyyaml/pull/550 -- drop Python 2.7
+* https://github.com/yaml/pyyaml/pull/553 -- Fix spelling of “hexadecimal”
+* https://github.com/yaml/pyyaml/pull/556 -- fix representation of Enum subclasses
+* https://github.com/yaml/pyyaml/pull/557 -- fix libyaml extension compiler warnings
+* https://github.com/yaml/pyyaml/pull/560 -- fix ResourceWarning on leaked file descriptors
+* https://github.com/yaml/pyyaml/pull/561 -- always require `Loader` arg to `yaml.load()`
+* https://github.com/yaml/pyyaml/pull/564 -- remove remaining direct distutils usage
+
+5.4.1 (2021-01-20)
+
+* https://github.com/yaml/pyyaml/pull/480 -- Fix stub compat with older pyyaml versions that may unwittingly load it
+
+5.4 (2021-01-19)
+
+* https://github.com/yaml/pyyaml/pull/407 -- Build modernization, remove distutils, fix metadata, build wheels, CI to GHA
+* https://github.com/yaml/pyyaml/pull/472 -- Fix for CVE-2020-14343, moves arbitrary python tags to UnsafeLoader
+* https://github.com/yaml/pyyaml/pull/441 -- Fix memory leak in implicit resolver setup
+* https://github.com/yaml/pyyaml/pull/392 -- Fix py2 copy support for timezone objects
+* https://github.com/yaml/pyyaml/pull/378 -- Fix compatibility with Jython
+
+5.3.1 (2020-03-18)
+
+* https://github.com/yaml/pyyaml/pull/386 -- Prevents arbitrary code execution during python/object/new constructor
+
+5.3 (2020-01-06)
+
+* https://github.com/yaml/pyyaml/pull/290 -- Use `is` instead of equality for comparing with `None`
+* https://github.com/yaml/pyyaml/pull/270 -- Fix typos and stylistic nit
+* https://github.com/yaml/pyyaml/pull/309 -- Fix up small typo
+* https://github.com/yaml/pyyaml/pull/161 -- Fix handling of __slots__
+* https://github.com/yaml/pyyaml/pull/358 -- Allow calling add_multi_constructor with None
+* https://github.com/yaml/pyyaml/pull/285 -- Add use of safe_load() function in README
+* https://github.com/yaml/pyyaml/pull/351 -- Fix reader for Unicode code points over 0xFFFF
+* https://github.com/yaml/pyyaml/pull/360 -- Enable certain unicode tests when maxunicode not > 0xffff
+* https://github.com/yaml/pyyaml/pull/359 -- Use full_load in yaml-highlight example
+* https://github.com/yaml/pyyaml/pull/244 -- Document that PyYAML is implemented with Cython
+* https://github.com/yaml/pyyaml/pull/329 -- Fix for Python 3.10
+* https://github.com/yaml/pyyaml/pull/310 -- Increase size of index, line, and column fields
+* https://github.com/yaml/pyyaml/pull/260 -- Remove some unused imports
+* https://github.com/yaml/pyyaml/pull/163 -- Create timezone-aware datetimes when parsed as such
+* https://github.com/yaml/pyyaml/pull/363 -- Add tests for timezone
+
+5.2 (2019-12-02)
+------------------
+
+* Repair incompatibilities introduced with 5.1. The default Loader was changed,
+  but several methods like add_constructor still used the old default
+  https://github.com/yaml/pyyaml/pull/279 -- A more flexible fix for custom tag constructors
+  https://github.com/yaml/pyyaml/pull/287 -- Change default loader for yaml.add_constructor
+  https://github.com/yaml/pyyaml/pull/305 -- Change default loader for add_implicit_resolver, add_path_resolver
+* Make FullLoader safer by removing python/object/apply from the default FullLoader
+  https://github.com/yaml/pyyaml/pull/347 -- Move constructor for object/apply to UnsafeConstructor
+* Fix bug introduced in 5.1 where quoting went wrong on systems with sys.maxunicode <= 0xffff
+  https://github.com/yaml/pyyaml/pull/276 -- Fix logic for quoting special characters
+* Other PRs:
+  https://github.com/yaml/pyyaml/pull/280 -- Update CHANGES for 5.1
+
+5.1.2 (2019-07-30)
+------------------
+
+* Re-release of 5.1 with regenerated Cython sources to build properly for Python 3.8b2+
+
+5.1.1 (2019-06-05)
+------------------
+
+* Re-release of 5.1 with regenerated Cython sources to build properly for Python 3.8b1
+
+5.1 (2019-03-13)
+----------------
+
+* https://github.com/yaml/pyyaml/pull/35 -- Some modernization of the test running
+* https://github.com/yaml/pyyaml/pull/42 -- Install tox in a virtualenv
+* https://github.com/yaml/pyyaml/pull/45 -- Allow colon in a plain scalar in a flow context
+* https://github.com/yaml/pyyaml/pull/48 -- Fix typos
+* https://github.com/yaml/pyyaml/pull/55 -- Improve RepresenterError creation
+* https://github.com/yaml/pyyaml/pull/59 -- Resolves #57, update readme issues link
+* https://github.com/yaml/pyyaml/pull/60 -- Document and test Python 3.6 support
+* https://github.com/yaml/pyyaml/pull/61 -- Use Travis CI built in pip cache support
+* https://github.com/yaml/pyyaml/pull/62 -- Remove tox workaround for Travis CI
+* https://github.com/yaml/pyyaml/pull/63 -- Adding support to Unicode characters over codepoint 0xffff
+* https://github.com/yaml/pyyaml/pull/75 -- add 3.12 changelog
+* https://github.com/yaml/pyyaml/pull/76 -- Fallback to Pure Python if Compilation fails
+* https://github.com/yaml/pyyaml/pull/84 -- Drop unsupported Python 3.3
+* https://github.com/yaml/pyyaml/pull/102 -- Include license file in the generated wheel package
+* https://github.com/yaml/pyyaml/pull/105 -- Removed Python 2.6 & 3.3 support
+* https://github.com/yaml/pyyaml/pull/111 -- Remove commented out Psyco code
+* https://github.com/yaml/pyyaml/pull/129 -- Remove call to `ord` in lib3 emitter code
+* https://github.com/yaml/pyyaml/pull/149 -- Test on Python 3.7-dev
+* https://github.com/yaml/pyyaml/pull/158 -- Support escaped slash in double quotes "\/"
+* https://github.com/yaml/pyyaml/pull/175 -- Updated link to pypi in release announcement
+* https://github.com/yaml/pyyaml/pull/181 -- Import Hashable from collections.abc
+* https://github.com/yaml/pyyaml/pull/194 -- Reverting https://github.com/yaml/pyyaml/pull/74
+* https://github.com/yaml/pyyaml/pull/195 -- Build libyaml on travis
+* https://github.com/yaml/pyyaml/pull/196 -- Force cython when building sdist
+* https://github.com/yaml/pyyaml/pull/254 -- Allow to turn off sorting keys in Dumper (2)
+* https://github.com/yaml/pyyaml/pull/256 -- Make default_flow_style=False
+* https://github.com/yaml/pyyaml/pull/257 -- Deprecate yaml.load and add FullLoader and UnsafeLoader classes
+* https://github.com/yaml/pyyaml/pull/261 -- Skip certain unicode tests when maxunicode not > 0xffff
+* https://github.com/yaml/pyyaml/pull/263 -- Windows Appveyor build
+
+3.13 (2018-07-05)
+-----------------
+
+* Resolved issues around PyYAML working in Python 3.7.
 
 3.12 (2016-08-28)
 -----------------
@@ -151,5 +263,5 @@
 
 * Initial release.  The version number reflects the codename
   of the project (PyYAML 3000) and differentiates it from
-  the abandoned PyYaml module. 
+  the abandoned PyYaml module.
 
diff --git a/LICENSE b/LICENSE
index 050ced2..2f1b8e1 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,5 @@
-Copyright (c) 2006 Kirill Simonov
+Copyright (c) 2017-2021 Ingy döt Net
+Copyright (c) 2006-2016 Kirill Simonov
 
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in
diff --git a/MANIFEST.in b/MANIFEST.in
index 185e780..3ab0c4f 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -1,7 +1,7 @@
-include README LICENSE CHANGES setup.py
+include CHANGES README LICENSE Makefile pyproject.toml setup.py
 recursive-include lib/yaml *.py
-recursive-include lib3/yaml *.py
+recursive-include lib/_yaml *.py
 recursive-include examples *.py *.cfg *.yaml
 recursive-include tests/data *
 recursive-include tests/lib *.py
-recursive-include tests/lib3 *.py
+recursive-include yaml *
diff --git a/Makefile b/Makefile
index da249e3..34a1d40 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 
-.PHONY: default build buildext force forceext install installext test testext dist clean
+.PHONY: build dist
 
-PYTHON=/usr/bin/python
+PYTHON=/usr/bin/python3
 TEST=
 PARAMETERS=
 
@@ -33,10 +33,19 @@
 	${PYTHON} setup.py test
 
 dist:
-	${PYTHON} setup.py --with-libyaml sdist --formats=zip,gztar
+	@# No longer uploading a zip file to pypi
+	@# ${PYTHON} setup.py --with-libyaml sdist --formats=zip,gztar
+	${PYTHON} setup.py --with-libyaml sdist --formats=gztar
 
 windist:
 	${PYTHON} setup.py --with-libyaml bdist_wininst
 
 clean:
 	${PYTHON} setup.py --with-libyaml clean -a
+	rm -fr \
+	    dist/ \
+	    lib/PyYAML.egg-info/ \
+	    lib/yaml/__pycache__/ \
+	    tests/lib/__pycache__/ \
+	    yaml/_yaml.c \
+
diff --git a/README b/README
deleted file mode 100644
index f09ff79..0000000
--- a/README
+++ /dev/null
@@ -1,34 +0,0 @@
-PyYAML - The next generation YAML parser and emitter for Python.
-
-To install, type 'python setup.py install'.
-
-By default, the setup.py script checks whether LibYAML is installed
-and if so, builds and installs LibYAML bindings.  To skip the check
-and force installation of LibYAML bindings, use the option '--with-libyaml':
-'python setup.py --with-libyaml install'.  To disable the check and
-skip building and installing LibYAML bindings, use '--without-libyaml':
-'python setup.py --without-libyaml install'.
-
-When LibYAML bindings are installed, you may use fast LibYAML-based
-parser and emitter as follows:
-
-    >>> yaml.load(stream, Loader=yaml.CLoader)
-    >>> yaml.dump(data, Dumper=yaml.CDumper)
-
-PyYAML includes a comprehensive test suite.  To run the tests,
-type 'python setup.py test'.
-
-For more information, check the PyYAML homepage:
-'http://pyyaml.org/wiki/PyYAML'.
-
-For PyYAML tutorial and reference, see:
-'http://pyyaml.org/wiki/PyYAMLDocumentation'.
-
-Post your questions and opinions to the YAML-Core mailing list:
-'http://lists.sourceforge.net/lists/listinfo/yaml-core'.
-
-Submit bug reports and feature requests to the PyYAML bug tracker:
-'https://github.com/yaml/pyyaml/issues'.
-
-PyYAML is written by Kirill Simonov <xi@resolvent.net>.  It is released
-under the MIT license. See the file LICENSE for more details.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..7d01da2
--- /dev/null
+++ b/README.md
@@ -0,0 +1,53 @@
+PyYAML
+======
+
+A full-featured YAML processing framework for Python
+
+## Installation
+
+To install, type `python setup.py install`.
+
+By default, the `setup.py` script checks whether LibYAML is installed and if
+so, builds and installs LibYAML bindings.
+To skip the check and force installation of LibYAML bindings, use the option
+`--with-libyaml`: `python setup.py --with-libyaml install`.
+To disable the check and skip building and installing LibYAML bindings, use
+`--without-libyaml`: `python setup.py --without-libyaml install`.
+
+When LibYAML bindings are installed, you may use fast LibYAML-based parser and
+emitter as follows:
+
+    >>> yaml.load(stream, Loader=yaml.CLoader)
+    >>> yaml.dump(data, Dumper=yaml.CDumper)
+
+If you don't trust the input YAML stream, you should use:
+
+    >>> yaml.safe_load(stream)
+
+## Testing
+
+PyYAML includes a comprehensive test suite.
+To run the tests, type `python setup.py test`.
+
+## Further Information
+
+* For more information, check the
+  [PyYAML homepage](https://github.com/yaml/pyyaml).
+
+* [PyYAML tutorial and reference](http://pyyaml.org/wiki/PyYAMLDocumentation).
+
+* Discuss PyYAML with the maintainers on
+  Matrix at https://matrix.to/#/#pyyaml:yaml.io or
+  IRC #pyyaml irc.libera.chat
+
+* Submit bug reports and feature requests to the
+  [PyYAML bug tracker](https://github.com/yaml/pyyaml/issues).
+
+## License
+
+The PyYAML module was written by Kirill Simonov <xi@resolvent.net>.
+It is currently maintained by the YAML and Python communities.
+
+PyYAML is released under the MIT license.
+
+See the file LICENSE for more details.
diff --git a/announcement.msg b/announcement.msg
index 2b21cf8..abc1bbe 100644
--- a/announcement.msg
+++ b/announcement.msg
@@ -1,36 +1,49 @@
-From: Kirill Simonov <xi@resolvent.net>
+From: Ingy döt Net <ingy@ingy.net>
 To: python-list@python.org, python-announce@python.org, yaml-core@lists.sourceforge.net
-Subject: [ANN] PyYAML-3.12: YAML parser and emitter for Python
+Subject: [ANN] PyYAML-6.0 Released
 
-========================
- Announcing PyYAML-3.12
-========================
+=====================
+Announcing PyYAML-6.0
+=====================
 
-A new bug fix release of PyYAML is now available:
+A new release of PyYAML is now available:
+https://github.com/yaml/pyyaml/releases/tag/6.0
 
-    http://pyyaml.org/wiki/PyYAML
+The previously-deprecated default loader selection in `yaml.load()` has
+been removed; `Loader` is now a required argument.
+
+Support for Python 2.7 and 3.5 has been dropped, and support for Python 3.10
+added. It now includes libyaml 0.2.5 extension wheels for MacOS M1
+(Apple Silicon/arm64), Linux s390x and Linux aarch64.
+
+Numerous other bugfixes and code cleanups are included in this release.
 
 
 Changes
 =======
 
-* Wheel packages for Windows binaries.
-* Adding an implicit resolver to a derived loader should not affect
-  the base loader (fixes issue #57).
-* Uniform representation for OrderedDict across different versions
-  of Python (fixes issue #61).
-* Fixed comparison to None warning (closes issue #64).
+* https://github.com/yaml/pyyaml/pull/327 -- Change README format to Markdown
+* https://github.com/yaml/pyyaml/pull/483 -- Add a test for YAML 1.1 types
+* https://github.com/yaml/pyyaml/pull/497 -- fix float resolver to ignore `.` and `._`
+* https://github.com/yaml/pyyaml/pull/550 -- drop Python 2.7
+* https://github.com/yaml/pyyaml/pull/553 -- Fix spelling of “hexadecimal”
+* https://github.com/yaml/pyyaml/pull/556 -- fix representation of Enum subclasses
+* https://github.com/yaml/pyyaml/pull/557 -- fix libyaml extension compiler warnings
+* https://github.com/yaml/pyyaml/pull/560 -- fix ResourceWarning on leaked file descriptors
+* https://github.com/yaml/pyyaml/pull/561 -- always require `Loader` arg to `yaml.load()`
+* https://github.com/yaml/pyyaml/pull/564 -- remove remaining direct distutils usage
 
 
 Resources
 =========
 
-PyYAML homepage: http://pyyaml.org/wiki/PyYAML
+PyYAML Matrix: https://matrix.to/#/#pyyaml:yaml.io
+PyYAML IRC Channel: #pyyaml on irc.libera.chat
+PyYAML homepage: https://github.com/yaml/pyyaml
 PyYAML documentation: http://pyyaml.org/wiki/PyYAMLDocumentation
-Source and binary installers: https://pypi.python.org/pypi/PyYAML/3.12
-
-PyYAML HG repository: https://bitbucket.org/xi/pyyaml
-Submit a bug report: https://bitbucket.org/xi/pyyaml/issues/new
+Source and binary installers: https://pypi.org/project/PyYAML/
+GitHub repository: https://github.com/yaml/pyyaml/
+Bug tracking: https://github.com/yaml/pyyaml/issues
 
 YAML homepage: http://yaml.org/
 YAML-core mailing list: http://lists.sourceforge.net/lists/listinfo/yaml-core
@@ -40,44 +53,61 @@
 ============
 
 YAML is a data serialization format designed for human readability and
-interaction with scripting languages.  PyYAML is a YAML parser and
-emitter for Python.
+interaction with scripting languages. PyYAML is a YAML parser and emitter for
+Python.
 
-PyYAML features a complete YAML 1.1 parser, Unicode support, pickle
-support, capable extension API, and sensible error messages.  PyYAML
-supports standard YAML tags and provides Python-specific tags that allow
-to represent an arbitrary Python object.
+PyYAML features a complete YAML 1.1 parser, Unicode support, pickle support,
+capable extension API, and sensible error messages. PyYAML supports standard
+YAML tags and provides Python-specific tags that allow to represent an
+arbitrary Python object.
 
-PyYAML is applicable for a broad range of tasks from complex
-configuration files to object serialization and persistence.
+PyYAML is applicable for a broad range of tasks from complex configuration
+files to object serialization and persistence.
 
 
 Example
 =======
 
+```
 >>> import yaml
 
->>> yaml.load("""
+>>> yaml.full_load("""
 ... name: PyYAML
 ... description: YAML parser and emitter for Python
-... homepage: http://pyyaml.org/wiki/PyYAML
+... homepage: https://github.com/yaml/pyyaml
 ... keywords: [YAML, serialization, configuration, persistence, pickle]
 ... """)
 {'keywords': ['YAML', 'serialization', 'configuration', 'persistence',
-'pickle'], 'homepage': 'http://pyyaml.org/wiki/PyYAML', 'description':
+'pickle'], 'homepage': 'https://github.com/yaml/pyyaml', 'description':
 'YAML parser and emitter for Python', 'name': 'PyYAML'}
 
->>> print yaml.dump(_)
+>>> print(yaml.dump(_))
 name: PyYAML
-homepage: http://pyyaml.org/wiki/PyYAML
+homepage: https://github.com/yaml/pyyaml
 description: YAML parser and emitter for Python
 keywords: [YAML, serialization, configuration, persistence, pickle]
+```
+
+Maintainers
+===========
+
+The following people are currently responsible for maintaining PyYAML:
+
+* Ingy döt Net
+* Matt Davis
+
+and many thanks to all who have contributed!
+See: https://github.com/yaml/pyyaml/pulls
 
 
 Copyright
 =========
 
-The PyYAML module is written by Kirill Simonov <xi@resolvent.net>.
+Copyright (c) 2017-2021 Ingy döt Net <ingy@ingy.net>
+Copyright (c) 2006-2016 Kirill Simonov <xi@resolvent.net>
+
+The PyYAML module was written by Kirill Simonov <xi@resolvent.net>.
+It is currently maintained by the YAML and Python communities.
 
 PyYAML is released under the MIT license.
-
+See the file LICENSE for more details.
diff --git a/examples/yaml-highlight/yaml_hl.py b/examples/yaml-highlight/yaml_hl.py
index d6f7bf4..96e0ae7 100755
--- a/examples/yaml-highlight/yaml_hl.py
+++ b/examples/yaml-highlight/yaml_hl.py
@@ -37,7 +37,7 @@
 class YAMLHighlight:
 
     def __init__(self, options):
-        config = yaml.load(file(options.config, 'rb').read())
+        config = yaml.full_load(file(options.config, 'rb').read())
         self.style = config[options.style]
         if options.input:
             self.input = file(options.input, 'rb')
diff --git a/ext/_yaml.h b/ext/_yaml.h
deleted file mode 100644
index 21fd6a9..0000000
--- a/ext/_yaml.h
+++ /dev/null
@@ -1,23 +0,0 @@
-
-#include <yaml.h>
-
-#if PY_MAJOR_VERSION < 3
-
-#define PyUnicode_FromString(s) PyUnicode_DecodeUTF8((s), strlen(s), "strict")
-
-#else
-
-#define PyString_CheckExact PyBytes_CheckExact
-#define PyString_AS_STRING  PyBytes_AS_STRING
-#define PyString_GET_SIZE   PyBytes_GET_SIZE
-#define PyString_FromStringAndSize  PyBytes_FromStringAndSize
-
-#endif
-
-#ifdef _MSC_VER	/* MS Visual C++ 6.0 */
-#if _MSC_VER == 1200
-
-#define PyLong_FromUnsignedLongLong(z)	PyInt_FromLong(i)
-
-#endif
-#endif
diff --git a/lib/_yaml/__init__.py b/lib/_yaml/__init__.py
new file mode 100644
index 0000000..7baa8c4
--- /dev/null
+++ b/lib/_yaml/__init__.py
@@ -0,0 +1,33 @@
+# This is a stub package designed to roughly emulate the _yaml
+# extension module, which previously existed as a standalone module
+# and has been moved into the `yaml` package namespace.
+# It does not perfectly mimic its old counterpart, but should get
+# close enough for anyone who's relying on it even when they shouldn't.
+import yaml
+
+# in some circumstances, the yaml module we imoprted may be from a different version, so we need
+# to tread carefully when poking at it here (it may not have the attributes we expect)
+if not getattr(yaml, '__with_libyaml__', False):
+    from sys import version_info
+
+    exc = ModuleNotFoundError if version_info >= (3, 6) else ImportError
+    raise exc("No module named '_yaml'")
+else:
+    from yaml._yaml import *
+    import warnings
+    warnings.warn(
+        'The _yaml extension module is now located at yaml._yaml'
+        ' and its location is subject to change.  To use the'
+        ' LibYAML-based parser and emitter, import from `yaml`:'
+        ' `from yaml import CLoader as Loader, CDumper as Dumper`.',
+        DeprecationWarning
+    )
+    del warnings
+    # Don't `del yaml` here because yaml is actually an existing
+    # namespace member of _yaml.
+
+__name__ = '_yaml'
+# If the module is top-level (i.e. not a part of any specific package)
+# then the attribute should be set to ''.
+# https://docs.python.org/3.8/library/types.html
+__package__ = ''
diff --git a/lib/yaml/__init__.py b/lib/yaml/__init__.py
index 153a74d..465041d 100644
--- a/lib/yaml/__init__.py
+++ b/lib/yaml/__init__.py
@@ -1,21 +1,31 @@
 
-from error import *
+from .error import *
 
-from tokens import *
-from events import *
-from nodes import *
+from .tokens import *
+from .events import *
+from .nodes import *
 
-from loader import *
-from dumper import *
+from .loader import *
+from .dumper import *
 
-__version__ = '3.12'
-
+__version__ = '6.0'
 try:
-    from cyaml import *
+    from .cyaml import *
     __with_libyaml__ = True
 except ImportError:
     __with_libyaml__ = False
 
+import io
+
+#------------------------------------------------------------------------------
+# XXX "Warnings control" is now deprecated. Leaving in the API function to not
+# break code that uses it.
+#------------------------------------------------------------------------------
+def warnings(settings=None):
+    if settings is None:
+        return {}
+
+#------------------------------------------------------------------------------
 def scan(stream, Loader=Loader):
     """
     Scan a YAML stream and produce scanning tokens.
@@ -61,28 +71,21 @@
     finally:
         loader.dispose()
 
-def load(stream, Loader=Loader):
+def load(stream, Loader):
     """
     Parse the first YAML document in a stream
     and produce the corresponding Python object.
-
-    By default resolve only basic YAML tags, if an alternate Loader is
-    provided, may be dangerous.
     """
     loader = Loader(stream)
     try:
         return loader.get_single_data()
     finally:
         loader.dispose()
-safe_load = load
 
-def load_all(stream, Loader=Loader):
+def load_all(stream, Loader):
     """
     Parse all YAML documents in a stream
     and produce corresponding Python objects.
-
-    By default resolve only basic YAML tags, if an alternate Loader is
-    provided, may be dangerous.
     """
     loader = Loader(stream)
     try:
@@ -90,23 +93,66 @@
             yield loader.get_data()
     finally:
         loader.dispose()
-safe_load_all = load_all
 
-def danger_load(stream):
+def full_load(stream):
     """
     Parse the first YAML document in a stream
     and produce the corresponding Python object.
-    When used on untrusted input, can result in arbitrary code execution.
-    """
-    return load(stream, DangerLoader)
 
-def danger_load_all(stream):
+    Resolve all tags except those known to be
+    unsafe on untrusted input.
+    """
+    return load(stream, FullLoader)
+
+def full_load_all(stream):
     """
     Parse all YAML documents in a stream
     and produce corresponding Python objects.
-    When used on untrusted input, can result in arbitrary code execution.
+
+    Resolve all tags except those known to be
+    unsafe on untrusted input.
     """
-    return load_all(stream, DangerLoader)
+    return load_all(stream, FullLoader)
+
+def safe_load(stream):
+    """
+    Parse the first YAML document in a stream
+    and produce the corresponding Python object.
+
+    Resolve only basic YAML tags. This is known
+    to be safe for untrusted input.
+    """
+    return load(stream, SafeLoader)
+
+def safe_load_all(stream):
+    """
+    Parse all YAML documents in a stream
+    and produce corresponding Python objects.
+
+    Resolve only basic YAML tags. This is known
+    to be safe for untrusted input.
+    """
+    return load_all(stream, SafeLoader)
+
+def unsafe_load(stream):
+    """
+    Parse the first YAML document in a stream
+    and produce the corresponding Python object.
+
+    Resolve all tags, even those known to be
+    unsafe on untrusted input.
+    """
+    return load(stream, UnsafeLoader)
+
+def unsafe_load_all(stream):
+    """
+    Parse all YAML documents in a stream
+    and produce corresponding Python objects.
+
+    Resolve all tags, even those known to be
+    unsafe on untrusted input.
+    """
+    return load_all(stream, UnsafeLoader)
 
 def emit(events, stream=None, Dumper=Dumper,
         canonical=None, indent=None, width=None,
@@ -117,8 +163,7 @@
     """
     getvalue = None
     if stream is None:
-        from StringIO import StringIO
-        stream = StringIO()
+        stream = io.StringIO()
         getvalue = stream.getvalue
     dumper = Dumper(stream, canonical=canonical, indent=indent, width=width,
             allow_unicode=allow_unicode, line_break=line_break)
@@ -133,7 +178,7 @@
 def serialize_all(nodes, stream=None, Dumper=Dumper,
         canonical=None, indent=None, width=None,
         allow_unicode=None, line_break=None,
-        encoding='utf-8', explicit_start=None, explicit_end=None,
+        encoding=None, explicit_start=None, explicit_end=None,
         version=None, tags=None):
     """
     Serialize a sequence of representation trees into a YAML stream.
@@ -142,10 +187,9 @@
     getvalue = None
     if stream is None:
         if encoding is None:
-            from StringIO import StringIO
+            stream = io.StringIO()
         else:
-            from cStringIO import StringIO
-        stream = StringIO()
+            stream = io.BytesIO()
         getvalue = stream.getvalue
     dumper = Dumper(stream, canonical=canonical, indent=indent, width=width,
             allow_unicode=allow_unicode, line_break=line_break,
@@ -169,11 +213,11 @@
     return serialize_all([node], stream, Dumper=Dumper, **kwds)
 
 def dump_all(documents, stream=None, Dumper=Dumper,
-        default_style=None, default_flow_style=None,
+        default_style=None, default_flow_style=False,
         canonical=None, indent=None, width=None,
         allow_unicode=None, line_break=None,
-        encoding='utf-8', explicit_start=None, explicit_end=None,
-        version=None, tags=None):
+        encoding=None, explicit_start=None, explicit_end=None,
+        version=None, tags=None, sort_keys=True):
     """
     Serialize a sequence of Python objects into a YAML stream.
     If stream is None, return the produced string instead.
@@ -181,17 +225,16 @@
     getvalue = None
     if stream is None:
         if encoding is None:
-            from StringIO import StringIO
+            stream = io.StringIO()
         else:
-            from cStringIO import StringIO
-        stream = StringIO()
+            stream = io.BytesIO()
         getvalue = stream.getvalue
     dumper = Dumper(stream, default_style=default_style,
             default_flow_style=default_flow_style,
             canonical=canonical, indent=indent, width=width,
             allow_unicode=allow_unicode, line_break=line_break,
             encoding=encoding, version=version, tags=tags,
-            explicit_start=explicit_start, explicit_end=explicit_end)
+            explicit_start=explicit_start, explicit_end=explicit_end, sort_keys=sort_keys)
     try:
         dumper.open()
         for data in documents:
@@ -201,15 +244,6 @@
         dumper.dispose()
     if getvalue:
         return getvalue()
-safe_dump_all = dump_all
-
-def danger_dump_all(documents, stream=None, **kwds):
-    """
-    Serialize a sequence of Python objects into a YAML stream.
-    Produce only basic YAML tags.
-    If stream is None, return the produced string instead.
-    """
-    return dump_all(documents, stream, Dumper=DangerDumper, **kwds)
 
 def dump(data, stream=None, Dumper=Dumper, **kwds):
     """
@@ -217,53 +251,80 @@
     If stream is None, return the produced string instead.
     """
     return dump_all([data], stream, Dumper=Dumper, **kwds)
-safe_dump = dump
 
-def danger_dump(data, stream=None, **kwds):
+def safe_dump_all(documents, stream=None, **kwds):
+    """
+    Serialize a sequence of Python objects into a YAML stream.
+    Produce only basic YAML tags.
+    If stream is None, return the produced string instead.
+    """
+    return dump_all(documents, stream, Dumper=SafeDumper, **kwds)
+
+def safe_dump(data, stream=None, **kwds):
     """
     Serialize a Python object into a YAML stream.
     Produce only basic YAML tags.
     If stream is None, return the produced string instead.
     """
-    return dump_all([data], stream, Dumper=DangerDumper, **kwds)
+    return dump_all([data], stream, Dumper=SafeDumper, **kwds)
 
 def add_implicit_resolver(tag, regexp, first=None,
-        Loader=Loader, Dumper=Dumper):
+        Loader=None, Dumper=Dumper):
     """
     Add an implicit scalar detector.
     If an implicit scalar value matches the given regexp,
     the corresponding tag is assigned to the scalar.
     first is a sequence of possible initial characters or None.
     """
-    Loader.add_implicit_resolver(tag, regexp, first)
+    if Loader is None:
+        loader.Loader.add_implicit_resolver(tag, regexp, first)
+        loader.FullLoader.add_implicit_resolver(tag, regexp, first)
+        loader.UnsafeLoader.add_implicit_resolver(tag, regexp, first)
+    else:
+        Loader.add_implicit_resolver(tag, regexp, first)
     Dumper.add_implicit_resolver(tag, regexp, first)
 
-def add_path_resolver(tag, path, kind=None, Loader=Loader, Dumper=Dumper):
+def add_path_resolver(tag, path, kind=None, Loader=None, Dumper=Dumper):
     """
     Add a path based resolver for the given tag.
     A path is a list of keys that forms a path
     to a node in the representation tree.
     Keys can be string values, integers, or None.
     """
-    Loader.add_path_resolver(tag, path, kind)
+    if Loader is None:
+        loader.Loader.add_path_resolver(tag, path, kind)
+        loader.FullLoader.add_path_resolver(tag, path, kind)
+        loader.UnsafeLoader.add_path_resolver(tag, path, kind)
+    else:
+        Loader.add_path_resolver(tag, path, kind)
     Dumper.add_path_resolver(tag, path, kind)
 
-def add_constructor(tag, constructor, Loader=Loader):
+def add_constructor(tag, constructor, Loader=None):
     """
     Add a constructor for the given tag.
     Constructor is a function that accepts a Loader instance
     and a node object and produces the corresponding Python object.
     """
-    Loader.add_constructor(tag, constructor)
+    if Loader is None:
+        loader.Loader.add_constructor(tag, constructor)
+        loader.FullLoader.add_constructor(tag, constructor)
+        loader.UnsafeLoader.add_constructor(tag, constructor)
+    else:
+        Loader.add_constructor(tag, constructor)
 
-def add_multi_constructor(tag_prefix, multi_constructor, Loader=Loader):
+def add_multi_constructor(tag_prefix, multi_constructor, Loader=None):
     """
     Add a multi-constructor for the given tag prefix.
     Multi-constructor is called for a node if its tag starts with tag_prefix.
     Multi-constructor accepts a Loader instance, a tag suffix,
     and a node object and produces the corresponding Python object.
     """
-    Loader.add_multi_constructor(tag_prefix, multi_constructor)
+    if Loader is None:
+        loader.Loader.add_multi_constructor(tag_prefix, multi_constructor)
+        loader.FullLoader.add_multi_constructor(tag_prefix, multi_constructor)
+        loader.UnsafeLoader.add_multi_constructor(tag_prefix, multi_constructor)
+    else:
+        Loader.add_multi_constructor(tag_prefix, multi_constructor)
 
 def add_representer(data_type, representer, Dumper=Dumper):
     """
@@ -290,35 +351,40 @@
     def __init__(cls, name, bases, kwds):
         super(YAMLObjectMetaclass, cls).__init__(name, bases, kwds)
         if 'yaml_tag' in kwds and kwds['yaml_tag'] is not None:
-            cls.yaml_loader.add_constructor(cls.yaml_tag, cls.from_yaml)
+            if isinstance(cls.yaml_loader, list):
+                for loader in cls.yaml_loader:
+                    loader.add_constructor(cls.yaml_tag, cls.from_yaml)
+            else:
+                cls.yaml_loader.add_constructor(cls.yaml_tag, cls.from_yaml)
+
             cls.yaml_dumper.add_representer(cls, cls.to_yaml)
 
-class YAMLObject(object):
+class YAMLObject(metaclass=YAMLObjectMetaclass):
     """
     An object that can dump itself to a YAML stream
     and load itself from a YAML stream.
     """
 
-    __metaclass__ = YAMLObjectMetaclass
     __slots__ = ()  # no direct instantiation, so allow immutable subclasses
 
-    yaml_loader = Loader
+    yaml_loader = [Loader, FullLoader, UnsafeLoader]
     yaml_dumper = Dumper
 
     yaml_tag = None
     yaml_flow_style = None
 
+    @classmethod
     def from_yaml(cls, loader, node):
         """
         Convert a representation node to a Python object.
         """
         return loader.construct_yaml_object(node, cls)
-    from_yaml = classmethod(from_yaml)
 
+    @classmethod
     def to_yaml(cls, dumper, data):
         """
         Convert a Python object to a representation node.
         """
         return dumper.represent_yaml_object(cls.yaml_tag, data, cls,
                 flow_style=cls.yaml_flow_style)
-    to_yaml = classmethod(to_yaml)
+
diff --git a/lib/yaml/composer.py b/lib/yaml/composer.py
index df85ef6..6d15cb4 100644
--- a/lib/yaml/composer.py
+++ b/lib/yaml/composer.py
@@ -1,14 +1,14 @@
 
 __all__ = ['Composer', 'ComposerError']
 
-from error import MarkedYAMLError
-from events import *
-from nodes import *
+from .error import MarkedYAMLError
+from .events import *
+from .nodes import *
 
 class ComposerError(MarkedYAMLError):
     pass
 
-class Composer(object):
+class Composer:
 
     def __init__(self):
         self.anchors = {}
@@ -66,14 +66,14 @@
             anchor = event.anchor
             if anchor not in self.anchors:
                 raise ComposerError(None, None, "found undefined alias %r"
-                        % anchor.encode('utf-8'), event.start_mark)
+                        % anchor, event.start_mark)
             return self.anchors[anchor]
         event = self.peek_event()
         anchor = event.anchor
         if anchor is not None:
             if anchor in self.anchors:
                 raise ComposerError("found duplicate anchor %r; first occurrence"
-                        % anchor.encode('utf-8'), self.anchors[anchor].start_mark,
+                        % anchor, self.anchors[anchor].start_mark,
                         "second occurrence", event.start_mark)
         self.descend_resolver(parent, index)
         if self.check_event(ScalarEvent):
@@ -88,7 +88,7 @@
     def compose_scalar_node(self, anchor):
         event = self.get_event()
         tag = event.tag
-        if tag is None or tag == u'!':
+        if tag is None or tag == '!':
             tag = self.resolve(ScalarNode, event.value, event.implicit)
         node = ScalarNode(tag, event.value,
                 event.start_mark, event.end_mark, style=event.style)
@@ -99,7 +99,7 @@
     def compose_sequence_node(self, anchor):
         start_event = self.get_event()
         tag = start_event.tag
-        if tag is None or tag == u'!':
+        if tag is None or tag == '!':
             tag = self.resolve(SequenceNode, None, start_event.implicit)
         node = SequenceNode(tag, [],
                 start_event.start_mark, None,
@@ -117,7 +117,7 @@
     def compose_mapping_node(self, anchor):
         start_event = self.get_event()
         tag = start_event.tag
-        if tag is None or tag == u'!':
+        if tag is None or tag == '!':
             tag = self.resolve(MappingNode, None, start_event.implicit)
         node = MappingNode(tag, [],
                 start_event.start_mark, None,
diff --git a/lib/yaml/constructor.py b/lib/yaml/constructor.py
index 635faac..619acd3 100644
--- a/lib/yaml/constructor.py
+++ b/lib/yaml/constructor.py
@@ -1,18 +1,22 @@
 
-__all__ = ['BaseConstructor', 'SafeConstructor', 'Constructor',
-    'ConstructorError']
+__all__ = [
+    'BaseConstructor',
+    'SafeConstructor',
+    'FullConstructor',
+    'UnsafeConstructor',
+    'Constructor',
+    'ConstructorError'
+]
 
-from error import *
-from nodes import *
+from .error import *
+from .nodes import *
 
-import datetime
-
-import binascii, re, sys, types
+import collections.abc, datetime, base64, binascii, re, sys, types
 
 class ConstructorError(MarkedYAMLError):
     pass
 
-class BaseConstructor(object):
+class BaseConstructor:
 
     yaml_constructors = {}
     yaml_multi_constructors = {}
@@ -27,6 +31,14 @@
         # If there are more documents available?
         return self.check_node()
 
+    def check_state_key(self, key):
+        """Block special attributes/methods from being set in a newly created
+        object, to prevent user-controlled methods from being called during
+        deserialization"""
+        if self.get_state_keys_blacklist_regexp().match(key):
+            raise ConstructorError(None, None,
+                "blacklisted key '%s' in instance state found" % (key,), None)
+
     def get_data(self):
         # Construct and return the next document.
         if self.check_node():
@@ -68,7 +80,7 @@
             constructor = self.yaml_constructors[node.tag]
         else:
             for tag_prefix in self.yaml_multi_constructors:
-                if node.tag.startswith(tag_prefix):
+                if tag_prefix is not None and node.tag.startswith(tag_prefix):
                     tag_suffix = node.tag[len(tag_prefix):]
                     constructor = self.yaml_multi_constructors[tag_prefix]
                     break
@@ -90,7 +102,7 @@
             data = constructor(self, tag_suffix, node)
         if isinstance(data, types.GeneratorType):
             generator = data
-            data = generator.next()
+            data = next(generator)
             if self.deep_construct:
                 for dummy in generator:
                     pass
@@ -125,11 +137,9 @@
         mapping = {}
         for key_node, value_node in node.value:
             key = self.construct_object(key_node, deep=deep)
-            try:
-                hash(key)
-            except TypeError, exc:
+            if not isinstance(key, collections.abc.Hashable):
                 raise ConstructorError("while constructing a mapping", node.start_mark,
-                        "found unacceptable key (%s)" % exc, key_node.start_mark)
+                        "found unhashable key", key_node.start_mark)
             value = self.construct_object(value_node, deep=deep)
             mapping[key] = value
         return mapping
@@ -146,33 +156,33 @@
             pairs.append((key, value))
         return pairs
 
+    @classmethod
     def add_constructor(cls, tag, constructor):
         if not 'yaml_constructors' in cls.__dict__:
             cls.yaml_constructors = cls.yaml_constructors.copy()
         cls.yaml_constructors[tag] = constructor
-    add_constructor = classmethod(add_constructor)
 
+    @classmethod
     def add_multi_constructor(cls, tag_prefix, multi_constructor):
         if not 'yaml_multi_constructors' in cls.__dict__:
             cls.yaml_multi_constructors = cls.yaml_multi_constructors.copy()
         cls.yaml_multi_constructors[tag_prefix] = multi_constructor
-    add_multi_constructor = classmethod(add_multi_constructor)
 
 class SafeConstructor(BaseConstructor):
 
     def construct_scalar(self, node):
         if isinstance(node, MappingNode):
             for key_node, value_node in node.value:
-                if key_node.tag == u'tag:yaml.org,2002:value':
+                if key_node.tag == 'tag:yaml.org,2002:value':
                     return self.construct_scalar(value_node)
-        return BaseConstructor.construct_scalar(self, node)
+        return super().construct_scalar(node)
 
     def flatten_mapping(self, node):
         merge = []
         index = 0
         while index < len(node.value):
             key_node, value_node = node.value[index]
-            if key_node.tag == u'tag:yaml.org,2002:merge':
+            if key_node.tag == 'tag:yaml.org,2002:merge':
                 del node.value[index]
                 if isinstance(value_node, MappingNode):
                     self.flatten_mapping(value_node)
@@ -194,8 +204,8 @@
                     raise ConstructorError("while constructing a mapping", node.start_mark,
                             "expected a mapping or list of mappings for merging, but found %s"
                             % value_node.id, value_node.start_mark)
-            elif key_node.tag == u'tag:yaml.org,2002:value':
-                key_node.tag = u'tag:yaml.org,2002:str'
+            elif key_node.tag == 'tag:yaml.org,2002:value':
+                key_node.tag = 'tag:yaml.org,2002:str'
                 index += 1
             else:
                 index += 1
@@ -205,19 +215,19 @@
     def construct_mapping(self, node, deep=False):
         if isinstance(node, MappingNode):
             self.flatten_mapping(node)
-        return BaseConstructor.construct_mapping(self, node, deep=deep)
+        return super().construct_mapping(node, deep=deep)
 
     def construct_yaml_null(self, node):
         self.construct_scalar(node)
         return None
 
     bool_values = {
-        u'yes':     True,
-        u'no':      False,
-        u'true':    True,
-        u'false':   False,
-        u'on':      True,
-        u'off':     False,
+        'yes':      True,
+        'no':       False,
+        'true':     True,
+        'false':    False,
+        'on':       True,
+        'off':      False,
     }
 
     def construct_yaml_bool(self, node):
@@ -225,7 +235,7 @@
         return self.bool_values[value.lower()]
 
     def construct_yaml_int(self, node):
-        value = str(self.construct_scalar(node))
+        value = self.construct_scalar(node)
         value = value.replace('_', '')
         sign = +1
         if value[0] == '-':
@@ -258,7 +268,7 @@
     nan_value = -inf_value/inf_value   # Trying to make a quiet NaN (like C99).
 
     def construct_yaml_float(self, node):
-        value = str(self.construct_scalar(node))
+        value = self.construct_scalar(node)
         value = value.replace('_', '').lower()
         sign = +1
         if value[0] == '-':
@@ -282,15 +292,23 @@
             return sign*float(value)
 
     def construct_yaml_binary(self, node):
-        value = self.construct_scalar(node)
         try:
-            return str(value).decode('base64')
-        except (binascii.Error, UnicodeEncodeError), exc:
+            value = self.construct_scalar(node).encode('ascii')
+        except UnicodeEncodeError as exc:
             raise ConstructorError(None, None,
-                    "failed to decode base64 data: %s" % exc, node.start_mark) 
+                    "failed to convert base64 data into ascii: %s" % exc,
+                    node.start_mark)
+        try:
+            if hasattr(base64, 'decodebytes'):
+                return base64.decodebytes(value)
+            else:
+                return base64.decodestring(value)
+        except binascii.Error as exc:
+            raise ConstructorError(None, None,
+                    "failed to decode base64 data: %s" % exc, node.start_mark)
 
     timestamp_regexp = re.compile(
-            ur'''^(?P<year>[0-9][0-9][0-9][0-9])
+            r'''^(?P<year>[0-9][0-9][0-9][0-9])
                 -(?P<month>[0-9][0-9]?)
                 -(?P<day>[0-9][0-9]?)
                 (?:(?:[Tt]|[ \t]+)
@@ -314,22 +332,23 @@
         minute = int(values['minute'])
         second = int(values['second'])
         fraction = 0
+        tzinfo = None
         if values['fraction']:
             fraction = values['fraction'][:6]
             while len(fraction) < 6:
                 fraction += '0'
             fraction = int(fraction)
-        delta = None
         if values['tz_sign']:
             tz_hour = int(values['tz_hour'])
             tz_minute = int(values['tz_minute'] or 0)
             delta = datetime.timedelta(hours=tz_hour, minutes=tz_minute)
             if values['tz_sign'] == '-':
                 delta = -delta
-        data = datetime.datetime(year, month, day, hour, minute, second, fraction)
-        if delta:
-            data -= delta
-        return data
+            tzinfo = datetime.timezone(delta)
+        elif values['tz']:
+            tzinfo = datetime.timezone.utc
+        return datetime.datetime(year, month, day, hour, minute, second, fraction,
+                                 tzinfo=tzinfo)
 
     def construct_yaml_omap(self, node):
         # Note: we do not check for duplicate keys, because it's too
@@ -381,11 +400,7 @@
         data.update(value)
 
     def construct_yaml_str(self, node):
-        value = self.construct_scalar(node)
-        try:
-            return value.encode('ascii')
-        except UnicodeEncodeError:
-            return value
+        return self.construct_scalar(node)
 
     def construct_yaml_seq(self, node):
         data = []
@@ -410,70 +425,96 @@
 
     def construct_undefined(self, node):
         raise ConstructorError(None, None,
-                "could not determine a constructor for the tag %r" % node.tag.encode('utf-8'),
+                "could not determine a constructor for the tag %r" % node.tag,
                 node.start_mark)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:null',
+        'tag:yaml.org,2002:null',
         SafeConstructor.construct_yaml_null)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:bool',
+        'tag:yaml.org,2002:bool',
         SafeConstructor.construct_yaml_bool)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:int',
+        'tag:yaml.org,2002:int',
         SafeConstructor.construct_yaml_int)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:float',
+        'tag:yaml.org,2002:float',
         SafeConstructor.construct_yaml_float)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:binary',
+        'tag:yaml.org,2002:binary',
         SafeConstructor.construct_yaml_binary)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:timestamp',
+        'tag:yaml.org,2002:timestamp',
         SafeConstructor.construct_yaml_timestamp)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:omap',
+        'tag:yaml.org,2002:omap',
         SafeConstructor.construct_yaml_omap)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:pairs',
+        'tag:yaml.org,2002:pairs',
         SafeConstructor.construct_yaml_pairs)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:set',
+        'tag:yaml.org,2002:set',
         SafeConstructor.construct_yaml_set)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:str',
+        'tag:yaml.org,2002:str',
         SafeConstructor.construct_yaml_str)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:seq',
+        'tag:yaml.org,2002:seq',
         SafeConstructor.construct_yaml_seq)
 
 SafeConstructor.add_constructor(
-        u'tag:yaml.org,2002:map',
+        'tag:yaml.org,2002:map',
         SafeConstructor.construct_yaml_map)
 
 SafeConstructor.add_constructor(None,
         SafeConstructor.construct_undefined)
 
-class Constructor(SafeConstructor):
+class FullConstructor(SafeConstructor):
+    # 'extend' is blacklisted because it is used by
+    # construct_python_object_apply to add `listitems` to a newly generate
+    # python instance
+    def get_state_keys_blacklist(self):
+        return ['^extend$', '^__.*__$']
+
+    def get_state_keys_blacklist_regexp(self):
+        if not hasattr(self, 'state_keys_blacklist_regexp'):
+            self.state_keys_blacklist_regexp = re.compile('(' + '|'.join(self.get_state_keys_blacklist()) + ')')
+        return self.state_keys_blacklist_regexp
 
     def construct_python_str(self, node):
-        return self.construct_scalar(node).encode('utf-8')
+        return self.construct_scalar(node)
 
     def construct_python_unicode(self, node):
         return self.construct_scalar(node)
 
+    def construct_python_bytes(self, node):
+        try:
+            value = self.construct_scalar(node).encode('ascii')
+        except UnicodeEncodeError as exc:
+            raise ConstructorError(None, None,
+                    "failed to convert base64 data into ascii: %s" % exc,
+                    node.start_mark)
+        try:
+            if hasattr(base64, 'decodebytes'):
+                return base64.decodebytes(value)
+            else:
+                return base64.decodestring(value)
+        except binascii.Error as exc:
+            raise ConstructorError(None, None,
+                    "failed to decode base64 data: %s" % exc, node.start_mark)
+
     def construct_python_long(self, node):
-        return long(self.construct_yaml_int(node))
+        return self.construct_yaml_int(node)
 
     def construct_python_complex(self, node):
        return complex(self.construct_scalar(node))
@@ -481,74 +522,77 @@
     def construct_python_tuple(self, node):
         return tuple(self.construct_sequence(node))
 
-    def find_python_module(self, name, mark):
+    def find_python_module(self, name, mark, unsafe=False):
         if not name:
             raise ConstructorError("while constructing a Python module", mark,
                     "expected non-empty name appended to the tag", mark)
-        try:
-            __import__(name)
-        except ImportError, exc:
+        if unsafe:
+            try:
+                __import__(name)
+            except ImportError as exc:
+                raise ConstructorError("while constructing a Python module", mark,
+                        "cannot find module %r (%s)" % (name, exc), mark)
+        if name not in sys.modules:
             raise ConstructorError("while constructing a Python module", mark,
-                    "cannot find module %r (%s)" % (name.encode('utf-8'), exc), mark)
+                    "module %r is not imported" % name, mark)
         return sys.modules[name]
 
-    def find_python_name(self, name, mark):
+    def find_python_name(self, name, mark, unsafe=False):
         if not name:
             raise ConstructorError("while constructing a Python object", mark,
                     "expected non-empty name appended to the tag", mark)
-        if u'.' in name:
+        if '.' in name:
             module_name, object_name = name.rsplit('.', 1)
         else:
-            module_name = '__builtin__'
+            module_name = 'builtins'
             object_name = name
-        try:
-            __import__(module_name)
-        except ImportError, exc:
+        if unsafe:
+            try:
+                __import__(module_name)
+            except ImportError as exc:
+                raise ConstructorError("while constructing a Python object", mark,
+                        "cannot find module %r (%s)" % (module_name, exc), mark)
+        if module_name not in sys.modules:
             raise ConstructorError("while constructing a Python object", mark,
-                    "cannot find module %r (%s)" % (module_name.encode('utf-8'), exc), mark)
+                    "module %r is not imported" % module_name, mark)
         module = sys.modules[module_name]
         if not hasattr(module, object_name):
             raise ConstructorError("while constructing a Python object", mark,
-                    "cannot find %r in the module %r" % (object_name.encode('utf-8'),
-                        module.__name__), mark)
+                    "cannot find %r in the module %r"
+                    % (object_name, module.__name__), mark)
         return getattr(module, object_name)
 
     def construct_python_name(self, suffix, node):
         value = self.construct_scalar(node)
         if value:
             raise ConstructorError("while constructing a Python name", node.start_mark,
-                    "expected the empty value, but found %r" % value.encode('utf-8'),
-                    node.start_mark)
+                    "expected the empty value, but found %r" % value, node.start_mark)
         return self.find_python_name(suffix, node.start_mark)
 
     def construct_python_module(self, suffix, node):
         value = self.construct_scalar(node)
         if value:
             raise ConstructorError("while constructing a Python module", node.start_mark,
-                    "expected the empty value, but found %r" % value.encode('utf-8'),
-                    node.start_mark)
+                    "expected the empty value, but found %r" % value, node.start_mark)
         return self.find_python_module(suffix, node.start_mark)
 
-    class classobj: pass
-
     def make_python_instance(self, suffix, node,
-            args=None, kwds=None, newobj=False):
+            args=None, kwds=None, newobj=False, unsafe=False):
         if not args:
             args = []
         if not kwds:
             kwds = {}
         cls = self.find_python_name(suffix, node.start_mark)
-        if newobj and isinstance(cls, type(self.classobj))  \
-                and not args and not kwds:
-            instance = self.classobj()
-            instance.__class__ = cls
-            return instance
-        elif newobj and isinstance(cls, type):
+        if not (unsafe or isinstance(cls, type)):
+            raise ConstructorError("while constructing a Python instance", node.start_mark,
+                    "expected a class, but found %r" % type(cls),
+                    node.start_mark)
+        if newobj and isinstance(cls, type):
             return cls.__new__(cls, *args, **kwds)
         else:
             return cls(*args, **kwds)
 
-    def set_python_instance_state(self, instance, state):
+    def set_python_instance_state(self, instance, state, unsafe=False):
         if hasattr(instance, '__setstate__'):
             instance.__setstate__(state)
         else:
@@ -556,11 +600,16 @@
             if isinstance(state, tuple) and len(state) == 2:
                 state, slotstate = state
             if hasattr(instance, '__dict__'):
+                if not unsafe and state:
+                    for key in state.keys():
+                        self.check_state_key(key)
                 instance.__dict__.update(state)
             elif state:
                 slotstate.update(state)
             for key, value in slotstate.items():
-                setattr(object, key, value)
+                if not unsafe:
+                    self.check_state_key(key)
+                setattr(instance, key, value)
 
     def construct_python_object(self, suffix, node):
         # Format:
@@ -609,67 +658,91 @@
     def construct_python_object_new(self, suffix, node):
         return self.construct_python_object_apply(suffix, node, newobj=True)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/none',
-    Constructor.construct_yaml_null)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/none',
+    FullConstructor.construct_yaml_null)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/bool',
-    Constructor.construct_yaml_bool)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/bool',
+    FullConstructor.construct_yaml_bool)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/str',
-    Constructor.construct_python_str)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/str',
+    FullConstructor.construct_python_str)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/unicode',
-    Constructor.construct_python_unicode)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/unicode',
+    FullConstructor.construct_python_unicode)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/int',
-    Constructor.construct_yaml_int)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/bytes',
+    FullConstructor.construct_python_bytes)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/long',
-    Constructor.construct_python_long)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/int',
+    FullConstructor.construct_yaml_int)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/float',
-    Constructor.construct_yaml_float)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/long',
+    FullConstructor.construct_python_long)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/complex',
-    Constructor.construct_python_complex)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/float',
+    FullConstructor.construct_yaml_float)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/list',
-    Constructor.construct_yaml_seq)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/complex',
+    FullConstructor.construct_python_complex)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/tuple',
-    Constructor.construct_python_tuple)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/list',
+    FullConstructor.construct_yaml_seq)
 
-Constructor.add_constructor(
-    u'tag:yaml.org,2002:python/dict',
-    Constructor.construct_yaml_map)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/tuple',
+    FullConstructor.construct_python_tuple)
 
-Constructor.add_multi_constructor(
-    u'tag:yaml.org,2002:python/name:',
-    Constructor.construct_python_name)
+FullConstructor.add_constructor(
+    'tag:yaml.org,2002:python/dict',
+    FullConstructor.construct_yaml_map)
 
-Constructor.add_multi_constructor(
-    u'tag:yaml.org,2002:python/module:',
-    Constructor.construct_python_module)
+FullConstructor.add_multi_constructor(
+    'tag:yaml.org,2002:python/name:',
+    FullConstructor.construct_python_name)
 
-Constructor.add_multi_constructor(
-    u'tag:yaml.org,2002:python/object:',
-    Constructor.construct_python_object)
+class UnsafeConstructor(FullConstructor):
 
-Constructor.add_multi_constructor(
-    u'tag:yaml.org,2002:python/object/apply:',
-    Constructor.construct_python_object_apply)
+    def find_python_module(self, name, mark):
+        return super(UnsafeConstructor, self).find_python_module(name, mark, unsafe=True)
 
-Constructor.add_multi_constructor(
-    u'tag:yaml.org,2002:python/object/new:',
-    Constructor.construct_python_object_new)
+    def find_python_name(self, name, mark):
+        return super(UnsafeConstructor, self).find_python_name(name, mark, unsafe=True)
 
+    def make_python_instance(self, suffix, node, args=None, kwds=None, newobj=False):
+        return super(UnsafeConstructor, self).make_python_instance(
+            suffix, node, args, kwds, newobj, unsafe=True)
+
+    def set_python_instance_state(self, instance, state):
+        return super(UnsafeConstructor, self).set_python_instance_state(
+            instance, state, unsafe=True)
+
+UnsafeConstructor.add_multi_constructor(
+    'tag:yaml.org,2002:python/module:',
+    UnsafeConstructor.construct_python_module)
+
+UnsafeConstructor.add_multi_constructor(
+    'tag:yaml.org,2002:python/object:',
+    UnsafeConstructor.construct_python_object)
+
+UnsafeConstructor.add_multi_constructor(
+    'tag:yaml.org,2002:python/object/new:',
+    UnsafeConstructor.construct_python_object_new)
+
+UnsafeConstructor.add_multi_constructor(
+    'tag:yaml.org,2002:python/object/apply:',
+    UnsafeConstructor.construct_python_object_apply)
+
+# Constructor is same as UnsafeConstructor. Need to leave this in place in case
+# people have extended it directly.
+class Constructor(UnsafeConstructor):
+    pass
diff --git a/lib/yaml/cyaml.py b/lib/yaml/cyaml.py
index 5371f63..0c21345 100644
--- a/lib/yaml/cyaml.py
+++ b/lib/yaml/cyaml.py
@@ -1,15 +1,17 @@
 
-__all__ = ['CBaseLoader', 'CSafeLoader', 'CLoader', 'CDangerLoader',
-        'CBaseDumper', 'CSafeDumper', 'CDumper', 'CDangerDumper']
+__all__ = [
+    'CBaseLoader', 'CSafeLoader', 'CFullLoader', 'CUnsafeLoader', 'CLoader',
+    'CBaseDumper', 'CSafeDumper', 'CDumper'
+]
 
-from _yaml import CParser, CEmitter
+from yaml._yaml import CParser, CEmitter
 
-from constructor import *
+from .constructor import *
 
-from serializer import *
-from representer import *
+from .serializer import *
+from .representer import *
 
-from resolver import *
+from .resolver import *
 
 class CBaseLoader(CParser, BaseConstructor, BaseResolver):
 
@@ -18,15 +20,28 @@
         BaseConstructor.__init__(self)
         BaseResolver.__init__(self)
 
-class CLoader(CParser, SafeConstructor, Resolver):
+class CSafeLoader(CParser, SafeConstructor, Resolver):
 
     def __init__(self, stream):
         CParser.__init__(self, stream)
         SafeConstructor.__init__(self)
         Resolver.__init__(self)
-CSafeLoader = CLoader
 
-class CDangerLoader(CParser, Constructor, Resolver):
+class CFullLoader(CParser, FullConstructor, Resolver):
+
+    def __init__(self, stream):
+        CParser.__init__(self, stream)
+        FullConstructor.__init__(self)
+        Resolver.__init__(self)
+
+class CUnsafeLoader(CParser, UnsafeConstructor, Resolver):
+
+    def __init__(self, stream):
+        CParser.__init__(self, stream)
+        UnsafeConstructor.__init__(self)
+        Resolver.__init__(self)
+
+class CLoader(CParser, Constructor, Resolver):
 
     def __init__(self, stream):
         CParser.__init__(self, stream)
@@ -36,51 +51,51 @@
 class CBaseDumper(CEmitter, BaseRepresenter, BaseResolver):
 
     def __init__(self, stream,
-            default_style=None, default_flow_style=None,
+            default_style=None, default_flow_style=False,
             canonical=None, indent=None, width=None,
             allow_unicode=None, line_break=None,
             encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
+            version=None, tags=None, sort_keys=True):
         CEmitter.__init__(self, stream, canonical=canonical,
                 indent=indent, width=width, encoding=encoding,
                 allow_unicode=allow_unicode, line_break=line_break,
                 explicit_start=explicit_start, explicit_end=explicit_end,
                 version=version, tags=tags)
         Representer.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
+                default_flow_style=default_flow_style, sort_keys=sort_keys)
         Resolver.__init__(self)
 
-class CDumper(CEmitter, SafeRepresenter, Resolver):
+class CSafeDumper(CEmitter, SafeRepresenter, Resolver):
 
     def __init__(self, stream,
-            default_style=None, default_flow_style=None,
+            default_style=None, default_flow_style=False,
             canonical=None, indent=None, width=None,
             allow_unicode=None, line_break=None,
             encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
+            version=None, tags=None, sort_keys=True):
         CEmitter.__init__(self, stream, canonical=canonical,
                 indent=indent, width=width, encoding=encoding,
                 allow_unicode=allow_unicode, line_break=line_break,
                 explicit_start=explicit_start, explicit_end=explicit_end,
                 version=version, tags=tags)
         SafeRepresenter.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
+                default_flow_style=default_flow_style, sort_keys=sort_keys)
         Resolver.__init__(self)
-CSafeDumper = CDumper
 
-class CDangerDumper(CEmitter, Serializer, Representer, Resolver):
+class CDumper(CEmitter, Serializer, Representer, Resolver):
 
     def __init__(self, stream,
-            default_style=None, default_flow_style=None,
+            default_style=None, default_flow_style=False,
             canonical=None, indent=None, width=None,
             allow_unicode=None, line_break=None,
             encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
+            version=None, tags=None, sort_keys=True):
         CEmitter.__init__(self, stream, canonical=canonical,
                 indent=indent, width=width, encoding=encoding,
                 allow_unicode=allow_unicode, line_break=line_break,
                 explicit_start=explicit_start, explicit_end=explicit_end,
                 version=version, tags=tags)
         Representer.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
+                default_flow_style=default_flow_style, sort_keys=sort_keys)
         Resolver.__init__(self)
+
diff --git a/lib/yaml/dumper.py b/lib/yaml/dumper.py
index 22fd927..6aadba5 100644
--- a/lib/yaml/dumper.py
+++ b/lib/yaml/dumper.py
@@ -1,19 +1,19 @@
 
-__all__ = ['BaseDumper', 'SafeDumper', 'Dumper', 'DangerDumper']
+__all__ = ['BaseDumper', 'SafeDumper', 'Dumper']
 
-from emitter import *
-from serializer import *
-from representer import *
-from resolver import *
+from .emitter import *
+from .serializer import *
+from .representer import *
+from .resolver import *
 
 class BaseDumper(Emitter, Serializer, BaseRepresenter, BaseResolver):
 
     def __init__(self, stream,
-            default_style=None, default_flow_style=None,
+            default_style=None, default_flow_style=False,
             canonical=None, indent=None, width=None,
             allow_unicode=None, line_break=None,
             encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
+            version=None, tags=None, sort_keys=True):
         Emitter.__init__(self, stream, canonical=canonical,
                 indent=indent, width=width,
                 allow_unicode=allow_unicode, line_break=line_break)
@@ -21,17 +21,17 @@
                 explicit_start=explicit_start, explicit_end=explicit_end,
                 version=version, tags=tags)
         Representer.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
+                default_flow_style=default_flow_style, sort_keys=sort_keys)
         Resolver.__init__(self)
 
-class Dumper(Emitter, Serializer, SafeRepresenter, Resolver):
+class SafeDumper(Emitter, Serializer, SafeRepresenter, Resolver):
 
     def __init__(self, stream,
-            default_style=None, default_flow_style=None,
+            default_style=None, default_flow_style=False,
             canonical=None, indent=None, width=None,
             allow_unicode=None, line_break=None,
             encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
+            version=None, tags=None, sort_keys=True):
         Emitter.__init__(self, stream, canonical=canonical,
                 indent=indent, width=width,
                 allow_unicode=allow_unicode, line_break=line_break)
@@ -39,18 +39,17 @@
                 explicit_start=explicit_start, explicit_end=explicit_end,
                 version=version, tags=tags)
         SafeRepresenter.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
+                default_flow_style=default_flow_style, sort_keys=sort_keys)
         Resolver.__init__(self)
-SafeDumper = Dumper
 
-class DangerDumper(Emitter, Serializer, Representer, Resolver):
+class Dumper(Emitter, Serializer, Representer, Resolver):
 
     def __init__(self, stream,
-            default_style=None, default_flow_style=None,
+            default_style=None, default_flow_style=False,
             canonical=None, indent=None, width=None,
             allow_unicode=None, line_break=None,
             encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
+            version=None, tags=None, sort_keys=True):
         Emitter.__init__(self, stream, canonical=canonical,
                 indent=indent, width=width,
                 allow_unicode=allow_unicode, line_break=line_break)
@@ -58,5 +57,6 @@
                 explicit_start=explicit_start, explicit_end=explicit_end,
                 version=version, tags=tags)
         Representer.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
+                default_flow_style=default_flow_style, sort_keys=sort_keys)
         Resolver.__init__(self)
+
diff --git a/lib/yaml/emitter.py b/lib/yaml/emitter.py
index 9561a82..a664d01 100644
--- a/lib/yaml/emitter.py
+++ b/lib/yaml/emitter.py
@@ -8,17 +8,13 @@
 
 __all__ = ['Emitter', 'EmitterError']
 
-import sys
-
-from error import YAMLError
-from events import *
-
-has_ucs4 = sys.maxunicode > 0xffff
+from .error import YAMLError
+from .events import *
 
 class EmitterError(YAMLError):
     pass
 
-class ScalarAnalysis(object):
+class ScalarAnalysis:
     def __init__(self, scalar, empty, multiline,
             allow_flow_plain, allow_block_plain,
             allow_single_quoted, allow_double_quoted,
@@ -32,11 +28,11 @@
         self.allow_double_quoted = allow_double_quoted
         self.allow_block = allow_block
 
-class Emitter(object):
+class Emitter:
 
     DEFAULT_TAG_PREFIXES = {
-        u'!' : u'!',
-        u'tag:yaml.org,2002:' : u'!!',
+        '!' : '!',
+        'tag:yaml.org,2002:' : '!!',
     }
 
     def __init__(self, stream, canonical=None, indent=None, width=None,
@@ -92,8 +88,8 @@
         self.best_width = 80
         if width and width > self.best_indent*2:
             self.best_width = width
-        self.best_line_break = u'\n'
-        if line_break in [u'\r', u'\n', u'\r\n']:
+        self.best_line_break = '\n'
+        if line_break in ['\r', '\n', '\r\n']:
             self.best_line_break = line_break
 
         # Tag prefixes.
@@ -163,7 +159,7 @@
 
     def expect_stream_start(self):
         if isinstance(self.event, StreamStartEvent):
-            if self.event.encoding and not getattr(self.stream, 'encoding', None):
+            if self.event.encoding and not hasattr(self.stream, 'encoding'):
                 self.encoding = self.event.encoding
             self.write_stream_start()
             self.state = self.expect_first_document_start
@@ -182,15 +178,14 @@
     def expect_document_start(self, first=False):
         if isinstance(self.event, DocumentStartEvent):
             if (self.event.version or self.event.tags) and self.open_ended:
-                self.write_indicator(u'...', True)
+                self.write_indicator('...', True)
                 self.write_indent()
             if self.event.version:
                 version_text = self.prepare_version(self.event.version)
                 self.write_version_directive(version_text)
             self.tag_prefixes = self.DEFAULT_TAG_PREFIXES.copy()
             if self.event.tags:
-                handles = self.event.tags.keys()
-                handles.sort()
+                handles = sorted(self.event.tags.keys())
                 for handle in handles:
                     prefix = self.event.tags[handle]
                     self.tag_prefixes[prefix] = handle
@@ -202,13 +197,13 @@
                     and not self.check_empty_document())
             if not implicit:
                 self.write_indent()
-                self.write_indicator(u'---', True)
+                self.write_indicator('---', True)
                 if self.canonical:
                     self.write_indent()
             self.state = self.expect_document_root
         elif isinstance(self.event, StreamEndEvent):
             if self.open_ended:
-                self.write_indicator(u'...', True)
+                self.write_indicator('...', True)
                 self.write_indent()
             self.write_stream_end()
             self.state = self.expect_nothing
@@ -220,7 +215,7 @@
         if isinstance(self.event, DocumentEndEvent):
             self.write_indent()
             if self.event.explicit:
-                self.write_indicator(u'...', True)
+                self.write_indicator('...', True)
                 self.write_indent()
             self.flush_stream()
             self.state = self.expect_document_start
@@ -243,7 +238,7 @@
         if isinstance(self.event, AliasEvent):
             self.expect_alias()
         elif isinstance(self.event, (ScalarEvent, CollectionStartEvent)):
-            self.process_anchor(u'&')
+            self.process_anchor('&')
             self.process_tag()
             if isinstance(self.event, ScalarEvent):
                 self.expect_scalar()
@@ -265,7 +260,7 @@
     def expect_alias(self):
         if self.event.anchor is None:
             raise EmitterError("anchor is not specified for alias")
-        self.process_anchor(u'*')
+        self.process_anchor('*')
         self.state = self.states.pop()
 
     def expect_scalar(self):
@@ -277,7 +272,7 @@
     # Flow sequence handlers.
 
     def expect_flow_sequence(self):
-        self.write_indicator(u'[', True, whitespace=True)
+        self.write_indicator('[', True, whitespace=True)
         self.flow_level += 1
         self.increase_indent(flow=True)
         self.state = self.expect_first_flow_sequence_item
@@ -286,7 +281,7 @@
         if isinstance(self.event, SequenceEndEvent):
             self.indent = self.indents.pop()
             self.flow_level -= 1
-            self.write_indicator(u']', False)
+            self.write_indicator(']', False)
             self.state = self.states.pop()
         else:
             if self.canonical or self.column > self.best_width:
@@ -299,12 +294,12 @@
             self.indent = self.indents.pop()
             self.flow_level -= 1
             if self.canonical:
-                self.write_indicator(u',', False)
+                self.write_indicator(',', False)
                 self.write_indent()
-            self.write_indicator(u']', False)
+            self.write_indicator(']', False)
             self.state = self.states.pop()
         else:
-            self.write_indicator(u',', False)
+            self.write_indicator(',', False)
             if self.canonical or self.column > self.best_width:
                 self.write_indent()
             self.states.append(self.expect_flow_sequence_item)
@@ -313,7 +308,7 @@
     # Flow mapping handlers.
 
     def expect_flow_mapping(self):
-        self.write_indicator(u'{', True, whitespace=True)
+        self.write_indicator('{', True, whitespace=True)
         self.flow_level += 1
         self.increase_indent(flow=True)
         self.state = self.expect_first_flow_mapping_key
@@ -322,7 +317,7 @@
         if isinstance(self.event, MappingEndEvent):
             self.indent = self.indents.pop()
             self.flow_level -= 1
-            self.write_indicator(u'}', False)
+            self.write_indicator('}', False)
             self.state = self.states.pop()
         else:
             if self.canonical or self.column > self.best_width:
@@ -331,7 +326,7 @@
                 self.states.append(self.expect_flow_mapping_simple_value)
                 self.expect_node(mapping=True, simple_key=True)
             else:
-                self.write_indicator(u'?', True)
+                self.write_indicator('?', True)
                 self.states.append(self.expect_flow_mapping_value)
                 self.expect_node(mapping=True)
 
@@ -340,31 +335,31 @@
             self.indent = self.indents.pop()
             self.flow_level -= 1
             if self.canonical:
-                self.write_indicator(u',', False)
+                self.write_indicator(',', False)
                 self.write_indent()
-            self.write_indicator(u'}', False)
+            self.write_indicator('}', False)
             self.state = self.states.pop()
         else:
-            self.write_indicator(u',', False)
+            self.write_indicator(',', False)
             if self.canonical or self.column > self.best_width:
                 self.write_indent()
             if not self.canonical and self.check_simple_key():
                 self.states.append(self.expect_flow_mapping_simple_value)
                 self.expect_node(mapping=True, simple_key=True)
             else:
-                self.write_indicator(u'?', True)
+                self.write_indicator('?', True)
                 self.states.append(self.expect_flow_mapping_value)
                 self.expect_node(mapping=True)
 
     def expect_flow_mapping_simple_value(self):
-        self.write_indicator(u':', False)
+        self.write_indicator(':', False)
         self.states.append(self.expect_flow_mapping_key)
         self.expect_node(mapping=True)
 
     def expect_flow_mapping_value(self):
         if self.canonical or self.column > self.best_width:
             self.write_indent()
-        self.write_indicator(u':', True)
+        self.write_indicator(':', True)
         self.states.append(self.expect_flow_mapping_key)
         self.expect_node(mapping=True)
 
@@ -384,7 +379,7 @@
             self.state = self.states.pop()
         else:
             self.write_indent()
-            self.write_indicator(u'-', True, indention=True)
+            self.write_indicator('-', True, indention=True)
             self.states.append(self.expect_block_sequence_item)
             self.expect_node(sequence=True)
 
@@ -407,18 +402,18 @@
                 self.states.append(self.expect_block_mapping_simple_value)
                 self.expect_node(mapping=True, simple_key=True)
             else:
-                self.write_indicator(u'?', True, indention=True)
+                self.write_indicator('?', True, indention=True)
                 self.states.append(self.expect_block_mapping_value)
                 self.expect_node(mapping=True)
 
     def expect_block_mapping_simple_value(self):
-        self.write_indicator(u':', False)
+        self.write_indicator(':', False)
         self.states.append(self.expect_block_mapping_key)
         self.expect_node(mapping=True)
 
     def expect_block_mapping_value(self):
         self.write_indent()
-        self.write_indicator(u':', True, indention=True)
+        self.write_indicator(':', True, indention=True)
         self.states.append(self.expect_block_mapping_key)
         self.expect_node(mapping=True)
 
@@ -437,7 +432,7 @@
             return False
         event = self.events[0]
         return (isinstance(event, ScalarEvent) and event.anchor is None
-                and event.tag is None and event.implicit and event.value == u'')
+                and event.tag is None and event.implicit and event.value == '')
 
     def check_simple_key(self):
         length = 0
@@ -482,7 +477,7 @@
                 self.prepared_tag = None
                 return
             if self.event.implicit[0] and tag is None:
-                tag = u'!'
+                tag = '!'
                 self.prepared_tag = None
         else:
             if (not self.canonical or tag is None) and self.event.implicit:
@@ -545,19 +540,18 @@
         major, minor = version
         if major != 1:
             raise EmitterError("unsupported YAML version: %d.%d" % (major, minor))
-        return u'%d.%d' % (major, minor)
+        return '%d.%d' % (major, minor)
 
     def prepare_tag_handle(self, handle):
         if not handle:
             raise EmitterError("tag handle must not be empty")
-        if handle[0] != u'!' or handle[-1] != u'!':
-            raise EmitterError("tag handle must start and end with '!': %r"
-                    % (handle.encode('utf-8')))
+        if handle[0] != '!' or handle[-1] != '!':
+            raise EmitterError("tag handle must start and end with '!': %r" % handle)
         for ch in handle[1:-1]:
-            if not (u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z'  \
-                    or ch in u'-_'):
+            if not ('0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'    \
+                    or ch in '-_'):
                 raise EmitterError("invalid character %r in the tag handle: %r"
-                        % (ch.encode('utf-8'), handle.encode('utf-8')))
+                        % (ch, handle))
         return handle
 
     def prepare_tag_prefix(self, prefix):
@@ -565,12 +559,12 @@
             raise EmitterError("tag prefix must not be empty")
         chunks = []
         start = end = 0
-        if prefix[0] == u'!':
+        if prefix[0] == '!':
             end = 1
         while end < len(prefix):
             ch = prefix[end]
-            if u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z'   \
-                    or ch in u'-;/?!:@&=+$,_.~*\'()[]':
+            if '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z' \
+                    or ch in '-;/?!:@&=+$,_.~*\'()[]':
                 end += 1
             else:
                 if start < end:
@@ -578,32 +572,31 @@
                 start = end = end+1
                 data = ch.encode('utf-8')
                 for ch in data:
-                    chunks.append(u'%%%02X' % ord(ch))
+                    chunks.append('%%%02X' % ord(ch))
         if start < end:
             chunks.append(prefix[start:end])
-        return u''.join(chunks)
+        return ''.join(chunks)
 
     def prepare_tag(self, tag):
         if not tag:
             raise EmitterError("tag must not be empty")
-        if tag == u'!':
+        if tag == '!':
             return tag
         handle = None
         suffix = tag
-        prefixes = self.tag_prefixes.keys()
-        prefixes.sort()
+        prefixes = sorted(self.tag_prefixes.keys())
         for prefix in prefixes:
             if tag.startswith(prefix)   \
-                    and (prefix == u'!' or len(prefix) < len(tag)):
+                    and (prefix == '!' or len(prefix) < len(tag)):
                 handle = self.tag_prefixes[prefix]
                 suffix = tag[len(prefix):]
         chunks = []
         start = end = 0
         while end < len(suffix):
             ch = suffix[end]
-            if u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z'   \
-                    or ch in u'-;/?:@&=+$,_.~*\'()[]'   \
-                    or (ch == u'!' and handle != u'!'):
+            if '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z' \
+                    or ch in '-;/?:@&=+$,_.~*\'()[]'   \
+                    or (ch == '!' and handle != '!'):
                 end += 1
             else:
                 if start < end:
@@ -611,23 +604,23 @@
                 start = end = end+1
                 data = ch.encode('utf-8')
                 for ch in data:
-                    chunks.append(u'%%%02X' % ord(ch))
+                    chunks.append('%%%02X' % ch)
         if start < end:
             chunks.append(suffix[start:end])
-        suffix_text = u''.join(chunks)
+        suffix_text = ''.join(chunks)
         if handle:
-            return u'%s%s' % (handle, suffix_text)
+            return '%s%s' % (handle, suffix_text)
         else:
-            return u'!<%s>' % suffix_text
+            return '!<%s>' % suffix_text
 
     def prepare_anchor(self, anchor):
         if not anchor:
             raise EmitterError("anchor must not be empty")
         for ch in anchor:
-            if not (u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z'  \
-                    or ch in u'-_'):
+            if not ('0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'    \
+                    or ch in '-_'):
                 raise EmitterError("invalid character %r in the anchor: %r"
-                        % (ch.encode('utf-8'), anchor.encode('utf-8')))
+                        % (ch, anchor))
         return anchor
 
     def analyze_scalar(self, scalar):
@@ -654,7 +647,7 @@
         space_break = False
 
         # Check document indicators.
-        if scalar.startswith(u'---') or scalar.startswith(u'...'):
+        if scalar.startswith('---') or scalar.startswith('...'):
             block_indicators = True
             flow_indicators = True
 
@@ -663,7 +656,7 @@
 
         # Last character or followed by a whitespace.
         followed_by_whitespace = (len(scalar) == 1 or
-                scalar[1] in u'\0 \t\r\n\x85\u2028\u2029')
+                scalar[1] in '\0 \t\r\n\x85\u2028\u2029')
 
         # The previous character is a space.
         previous_space = False
@@ -678,35 +671,35 @@
             # Check for indicators.
             if index == 0:
                 # Leading indicators are special characters.
-                if ch in u'#,[]{}&*!|>\'\"%@`':
+                if ch in '#,[]{}&*!|>\'\"%@`':
                     flow_indicators = True
                     block_indicators = True
-                if ch in u'?:':
+                if ch in '?:':
                     flow_indicators = True
                     if followed_by_whitespace:
                         block_indicators = True
-                if ch == u'-' and followed_by_whitespace:
+                if ch == '-' and followed_by_whitespace:
                     flow_indicators = True
                     block_indicators = True
             else:
                 # Some indicators cannot appear within a scalar as well.
-                if ch in u',?[]{}':
+                if ch in ',?[]{}':
                     flow_indicators = True
-                if ch == u':':
+                if ch == ':':
                     flow_indicators = True
                     if followed_by_whitespace:
                         block_indicators = True
-                if ch == u'#' and preceded_by_whitespace:
+                if ch == '#' and preceded_by_whitespace:
                     flow_indicators = True
                     block_indicators = True
 
             # Check for line breaks, special, and unicode characters.
-            if ch in u'\n\x85\u2028\u2029':
+            if ch in '\n\x85\u2028\u2029':
                 line_breaks = True
-            if not (ch == u'\n' or u'\x20' <= ch <= u'\x7E'):
-                if (ch == u'\x85' or u'\xA0' <= ch <= u'\uD7FF'
-                        or u'\uE000' <= ch <= u'\uFFFD'
-                        or ((not has_ucs4) or (u'\U00010000' <= ch < u'\U0010ffff'))) and ch != u'\uFEFF':
+            if not (ch == '\n' or '\x20' <= ch <= '\x7E'):
+                if (ch == '\x85' or '\xA0' <= ch <= '\uD7FF'
+                        or '\uE000' <= ch <= '\uFFFD'
+                        or '\U00010000' <= ch < '\U0010ffff') and ch != '\uFEFF':
                     unicode_characters = True
                     if not self.allow_unicode:
                         special_characters = True
@@ -714,7 +707,7 @@
                     special_characters = True
 
             # Detect important whitespace combinations.
-            if ch == u' ':
+            if ch == ' ':
                 if index == 0:
                     leading_space = True
                 if index == len(scalar)-1:
@@ -723,7 +716,7 @@
                     break_space = True
                 previous_space = True
                 previous_break = False
-            elif ch in u'\n\x85\u2028\u2029':
+            elif ch in '\n\x85\u2028\u2029':
                 if index == 0:
                     leading_break = True
                 if index == len(scalar)-1:
@@ -738,9 +731,9 @@
 
             # Prepare for the next character.
             index += 1
-            preceded_by_whitespace = (ch in u'\0 \t\r\n\x85\u2028\u2029')
+            preceded_by_whitespace = (ch in '\0 \t\r\n\x85\u2028\u2029')
             followed_by_whitespace = (index+1 >= len(scalar) or
-                    scalar[index+1] in u'\0 \t\r\n\x85\u2028\u2029')
+                    scalar[index+1] in '\0 \t\r\n\x85\u2028\u2029')
 
         # Let's decide what styles are allowed.
         allow_flow_plain = True
@@ -799,7 +792,7 @@
     def write_stream_start(self):
         # Write BOM if needed.
         if self.encoding and self.encoding.startswith('utf-16'):
-            self.stream.write(u'\uFEFF'.encode(self.encoding))
+            self.stream.write('\uFEFF'.encode(self.encoding))
 
     def write_stream_end(self):
         self.flush_stream()
@@ -809,7 +802,7 @@
         if self.whitespace or not need_whitespace:
             data = indicator
         else:
-            data = u' '+indicator
+            data = ' '+indicator
         self.whitespace = whitespace
         self.indention = self.indention and indention
         self.column += len(data)
@@ -825,7 +818,7 @@
             self.write_line_break()
         if self.column < indent:
             self.whitespace = True
-            data = u' '*(indent-self.column)
+            data = ' '*(indent-self.column)
             self.column = indent
             if self.encoding:
                 data = data.encode(self.encoding)
@@ -843,14 +836,14 @@
         self.stream.write(data)
 
     def write_version_directive(self, version_text):
-        data = u'%%YAML %s' % version_text
+        data = '%%YAML %s' % version_text
         if self.encoding:
             data = data.encode(self.encoding)
         self.stream.write(data)
         self.write_line_break()
 
     def write_tag_directive(self, handle_text, prefix_text):
-        data = u'%%TAG %s %s' % (handle_text, prefix_text)
+        data = '%%TAG %s %s' % (handle_text, prefix_text)
         if self.encoding:
             data = data.encode(self.encoding)
         self.stream.write(data)
@@ -859,7 +852,7 @@
     # Scalar streams.
 
     def write_single_quoted(self, text, split=True):
-        self.write_indicator(u'\'', True)
+        self.write_indicator('\'', True)
         spaces = False
         breaks = False
         start = end = 0
@@ -868,7 +861,7 @@
             if end < len(text):
                 ch = text[end]
             if spaces:
-                if ch is None or ch != u' ':
+                if ch is None or ch != ' ':
                     if start+1 == end and self.column > self.best_width and split   \
                             and start != 0 and end != len(text):
                         self.write_indent()
@@ -880,18 +873,18 @@
                         self.stream.write(data)
                     start = end
             elif breaks:
-                if ch is None or ch not in u'\n\x85\u2028\u2029':
-                    if text[start] == u'\n':
+                if ch is None or ch not in '\n\x85\u2028\u2029':
+                    if text[start] == '\n':
                         self.write_line_break()
                     for br in text[start:end]:
-                        if br == u'\n':
+                        if br == '\n':
                             self.write_line_break()
                         else:
                             self.write_line_break(br)
                     self.write_indent()
                     start = end
             else:
-                if ch is None or ch in u' \n\x85\u2028\u2029' or ch == u'\'':
+                if ch is None or ch in ' \n\x85\u2028\u2029' or ch == '\'':
                     if start < end:
                         data = text[start:end]
                         self.column += len(data)
@@ -899,49 +892,49 @@
                             data = data.encode(self.encoding)
                         self.stream.write(data)
                         start = end
-            if ch == u'\'':
-                data = u'\'\''
+            if ch == '\'':
+                data = '\'\''
                 self.column += 2
                 if self.encoding:
                     data = data.encode(self.encoding)
                 self.stream.write(data)
                 start = end + 1
             if ch is not None:
-                spaces = (ch == u' ')
-                breaks = (ch in u'\n\x85\u2028\u2029')
+                spaces = (ch == ' ')
+                breaks = (ch in '\n\x85\u2028\u2029')
             end += 1
-        self.write_indicator(u'\'', False)
+        self.write_indicator('\'', False)
 
     ESCAPE_REPLACEMENTS = {
-        u'\0':      u'0',
-        u'\x07':    u'a',
-        u'\x08':    u'b',
-        u'\x09':    u't',
-        u'\x0A':    u'n',
-        u'\x0B':    u'v',
-        u'\x0C':    u'f',
-        u'\x0D':    u'r',
-        u'\x1B':    u'e',
-        u'\"':      u'\"',
-        u'\\':      u'\\',
-        u'\x85':    u'N',
-        u'\xA0':    u'_',
-        u'\u2028':  u'L',
-        u'\u2029':  u'P',
+        '\0':       '0',
+        '\x07':     'a',
+        '\x08':     'b',
+        '\x09':     't',
+        '\x0A':     'n',
+        '\x0B':     'v',
+        '\x0C':     'f',
+        '\x0D':     'r',
+        '\x1B':     'e',
+        '\"':       '\"',
+        '\\':       '\\',
+        '\x85':     'N',
+        '\xA0':     '_',
+        '\u2028':   'L',
+        '\u2029':   'P',
     }
 
     def write_double_quoted(self, text, split=True):
-        self.write_indicator(u'"', True)
+        self.write_indicator('"', True)
         start = end = 0
         while end <= len(text):
             ch = None
             if end < len(text):
                 ch = text[end]
-            if ch is None or ch in u'"\\\x85\u2028\u2029\uFEFF' \
-                    or not (u'\x20' <= ch <= u'\x7E'
+            if ch is None or ch in '"\\\x85\u2028\u2029\uFEFF' \
+                    or not ('\x20' <= ch <= '\x7E'
                         or (self.allow_unicode
-                            and (u'\xA0' <= ch <= u'\uD7FF'
-                                or u'\uE000' <= ch <= u'\uFFFD'))):
+                            and ('\xA0' <= ch <= '\uD7FF'
+                                or '\uE000' <= ch <= '\uFFFD'))):
                 if start < end:
                     data = text[start:end]
                     self.column += len(data)
@@ -951,21 +944,21 @@
                     start = end
                 if ch is not None:
                     if ch in self.ESCAPE_REPLACEMENTS:
-                        data = u'\\'+self.ESCAPE_REPLACEMENTS[ch]
-                    elif ch <= u'\xFF':
-                        data = u'\\x%02X' % ord(ch)
-                    elif ch <= u'\uFFFF':
-                        data = u'\\u%04X' % ord(ch)
+                        data = '\\'+self.ESCAPE_REPLACEMENTS[ch]
+                    elif ch <= '\xFF':
+                        data = '\\x%02X' % ord(ch)
+                    elif ch <= '\uFFFF':
+                        data = '\\u%04X' % ord(ch)
                     else:
-                        data = u'\\U%08X' % ord(ch)
+                        data = '\\U%08X' % ord(ch)
                     self.column += len(data)
                     if self.encoding:
                         data = data.encode(self.encoding)
                     self.stream.write(data)
                     start = end+1
-            if 0 < end < len(text)-1 and (ch == u' ' or start >= end)   \
+            if 0 < end < len(text)-1 and (ch == ' ' or start >= end)    \
                     and self.column+(end-start) > self.best_width and split:
-                data = text[start:end]+u'\\'
+                data = text[start:end]+'\\'
                 if start < end:
                     start = end
                 self.column += len(data)
@@ -975,30 +968,30 @@
                 self.write_indent()
                 self.whitespace = False
                 self.indention = False
-                if text[start] == u' ':
-                    data = u'\\'
+                if text[start] == ' ':
+                    data = '\\'
                     self.column += len(data)
                     if self.encoding:
                         data = data.encode(self.encoding)
                     self.stream.write(data)
             end += 1
-        self.write_indicator(u'"', False)
+        self.write_indicator('"', False)
 
     def determine_block_hints(self, text):
-        hints = u''
+        hints = ''
         if text:
-            if text[0] in u' \n\x85\u2028\u2029':
-                hints += unicode(self.best_indent)
-            if text[-1] not in u'\n\x85\u2028\u2029':
-                hints += u'-'
-            elif len(text) == 1 or text[-2] in u'\n\x85\u2028\u2029':
-                hints += u'+'
+            if text[0] in ' \n\x85\u2028\u2029':
+                hints += str(self.best_indent)
+            if text[-1] not in '\n\x85\u2028\u2029':
+                hints += '-'
+            elif len(text) == 1 or text[-2] in '\n\x85\u2028\u2029':
+                hints += '+'
         return hints
 
     def write_folded(self, text):
         hints = self.determine_block_hints(text)
-        self.write_indicator(u'>'+hints, True)
-        if hints[-1:] == u'+':
+        self.write_indicator('>'+hints, True)
+        if hints[-1:] == '+':
             self.open_ended = True
         self.write_line_break()
         leading_space = True
@@ -1010,13 +1003,13 @@
             if end < len(text):
                 ch = text[end]
             if breaks:
-                if ch is None or ch not in u'\n\x85\u2028\u2029':
-                    if not leading_space and ch is not None and ch != u' '  \
-                            and text[start] == u'\n':
+                if ch is None or ch not in '\n\x85\u2028\u2029':
+                    if not leading_space and ch is not None and ch != ' '   \
+                            and text[start] == '\n':
                         self.write_line_break()
-                    leading_space = (ch == u' ')
+                    leading_space = (ch == ' ')
                     for br in text[start:end]:
-                        if br == u'\n':
+                        if br == '\n':
                             self.write_line_break()
                         else:
                             self.write_line_break(br)
@@ -1024,7 +1017,7 @@
                         self.write_indent()
                     start = end
             elif spaces:
-                if ch != u' ':
+                if ch != ' ':
                     if start+1 == end and self.column > self.best_width:
                         self.write_indent()
                     else:
@@ -1035,7 +1028,7 @@
                         self.stream.write(data)
                     start = end
             else:
-                if ch is None or ch in u' \n\x85\u2028\u2029':
+                if ch is None or ch in ' \n\x85\u2028\u2029':
                     data = text[start:end]
                     self.column += len(data)
                     if self.encoding:
@@ -1045,14 +1038,14 @@
                         self.write_line_break()
                     start = end
             if ch is not None:
-                breaks = (ch in u'\n\x85\u2028\u2029')
-                spaces = (ch == u' ')
+                breaks = (ch in '\n\x85\u2028\u2029')
+                spaces = (ch == ' ')
             end += 1
 
     def write_literal(self, text):
         hints = self.determine_block_hints(text)
-        self.write_indicator(u'|'+hints, True)
-        if hints[-1:] == u'+':
+        self.write_indicator('|'+hints, True)
+        if hints[-1:] == '+':
             self.open_ended = True
         self.write_line_break()
         breaks = True
@@ -1062,9 +1055,9 @@
             if end < len(text):
                 ch = text[end]
             if breaks:
-                if ch is None or ch not in u'\n\x85\u2028\u2029':
+                if ch is None or ch not in '\n\x85\u2028\u2029':
                     for br in text[start:end]:
-                        if br == u'\n':
+                        if br == '\n':
                             self.write_line_break()
                         else:
                             self.write_line_break(br)
@@ -1072,7 +1065,7 @@
                         self.write_indent()
                     start = end
             else:
-                if ch is None or ch in u'\n\x85\u2028\u2029':
+                if ch is None or ch in '\n\x85\u2028\u2029':
                     data = text[start:end]
                     if self.encoding:
                         data = data.encode(self.encoding)
@@ -1081,7 +1074,7 @@
                         self.write_line_break()
                     start = end
             if ch is not None:
-                breaks = (ch in u'\n\x85\u2028\u2029')
+                breaks = (ch in '\n\x85\u2028\u2029')
             end += 1
 
     def write_plain(self, text, split=True):
@@ -1090,7 +1083,7 @@
         if not text:
             return
         if not self.whitespace:
-            data = u' '
+            data = ' '
             self.column += len(data)
             if self.encoding:
                 data = data.encode(self.encoding)
@@ -1105,7 +1098,7 @@
             if end < len(text):
                 ch = text[end]
             if spaces:
-                if ch != u' ':
+                if ch != ' ':
                     if start+1 == end and self.column > self.best_width and split:
                         self.write_indent()
                         self.whitespace = False
@@ -1118,11 +1111,11 @@
                         self.stream.write(data)
                     start = end
             elif breaks:
-                if ch not in u'\n\x85\u2028\u2029':
-                    if text[start] == u'\n':
+                if ch not in '\n\x85\u2028\u2029':
+                    if text[start] == '\n':
                         self.write_line_break()
                     for br in text[start:end]:
-                        if br == u'\n':
+                        if br == '\n':
                             self.write_line_break()
                         else:
                             self.write_line_break(br)
@@ -1131,7 +1124,7 @@
                     self.indention = False
                     start = end
             else:
-                if ch is None or ch in u' \n\x85\u2028\u2029':
+                if ch is None or ch in ' \n\x85\u2028\u2029':
                     data = text[start:end]
                     self.column += len(data)
                     if self.encoding:
@@ -1139,6 +1132,6 @@
                     self.stream.write(data)
                     start = end
             if ch is not None:
-                spaces = (ch == u' ')
-                breaks = (ch in u'\n\x85\u2028\u2029')
+                spaces = (ch == ' ')
+                breaks = (ch in '\n\x85\u2028\u2029')
             end += 1
diff --git a/lib/yaml/error.py b/lib/yaml/error.py
index 577686d..b796b4d 100644
--- a/lib/yaml/error.py
+++ b/lib/yaml/error.py
@@ -1,7 +1,7 @@
 
 __all__ = ['Mark', 'YAMLError', 'MarkedYAMLError']
 
-class Mark(object):
+class Mark:
 
     def __init__(self, name, index, line, column, buffer, pointer):
         self.name = name
@@ -16,7 +16,7 @@
             return None
         head = ''
         start = self.pointer
-        while start > 0 and self.buffer[start-1] not in u'\0\r\n\x85\u2028\u2029':
+        while start > 0 and self.buffer[start-1] not in '\0\r\n\x85\u2028\u2029':
             start -= 1
             if self.pointer-start > max_length/2-1:
                 head = ' ... '
@@ -24,13 +24,13 @@
                 break
         tail = ''
         end = self.pointer
-        while end < len(self.buffer) and self.buffer[end] not in u'\0\r\n\x85\u2028\u2029':
+        while end < len(self.buffer) and self.buffer[end] not in '\0\r\n\x85\u2028\u2029':
             end += 1
             if end-self.pointer > max_length/2-1:
                 tail = ' ... '
                 end -= 5
                 break
-        snippet = self.buffer[start:end].encode('utf-8')
+        snippet = self.buffer[start:end]
         return ' '*indent + head + snippet + tail + '\n'  \
                 + ' '*(indent+self.pointer-start+len(head)) + '^'
 
diff --git a/lib/yaml/loader.py b/lib/yaml/loader.py
index 6b18527..e90c112 100644
--- a/lib/yaml/loader.py
+++ b/lib/yaml/loader.py
@@ -1,12 +1,12 @@
 
-__all__ = ['BaseLoader', 'SafeLoader', 'Loader', 'DangerLoader']
+__all__ = ['BaseLoader', 'FullLoader', 'SafeLoader', 'Loader', 'UnsafeLoader']
 
-from reader import *
-from scanner import *
-from parser import *
-from composer import *
-from constructor import *
-from resolver import *
+from .reader import *
+from .scanner import *
+from .parser import *
+from .composer import *
+from .constructor import *
+from .resolver import *
 
 class BaseLoader(Reader, Scanner, Parser, Composer, BaseConstructor, BaseResolver):
 
@@ -18,7 +18,17 @@
         BaseConstructor.__init__(self)
         BaseResolver.__init__(self)
 
-class Loader(Reader, Scanner, Parser, Composer, SafeConstructor, Resolver):
+class FullLoader(Reader, Scanner, Parser, Composer, FullConstructor, Resolver):
+
+    def __init__(self, stream):
+        Reader.__init__(self, stream)
+        Scanner.__init__(self)
+        Parser.__init__(self)
+        Composer.__init__(self)
+        FullConstructor.__init__(self)
+        Resolver.__init__(self)
+
+class SafeLoader(Reader, Scanner, Parser, Composer, SafeConstructor, Resolver):
 
     def __init__(self, stream):
         Reader.__init__(self, stream)
@@ -27,9 +37,22 @@
         Composer.__init__(self)
         SafeConstructor.__init__(self)
         Resolver.__init__(self)
-SafeLoader = Loader
 
-class DangerLoader(Reader, Scanner, Parser, Composer, Constructor, Resolver):
+class Loader(Reader, Scanner, Parser, Composer, Constructor, Resolver):
+
+    def __init__(self, stream):
+        Reader.__init__(self, stream)
+        Scanner.__init__(self)
+        Parser.__init__(self)
+        Composer.__init__(self)
+        Constructor.__init__(self)
+        Resolver.__init__(self)
+
+# UnsafeLoader is the same as Loader (which is and was always unsafe on
+# untrusted input). Use of either Loader or UnsafeLoader should be rare, since
+# FullLoad should be able to load almost all YAML safely. Loader is left intact
+# to ensure backwards compatibility.
+class UnsafeLoader(Reader, Scanner, Parser, Composer, Constructor, Resolver):
 
     def __init__(self, stream):
         Reader.__init__(self, stream)
diff --git a/lib/yaml/parser.py b/lib/yaml/parser.py
index f9e3057..13a5995 100644
--- a/lib/yaml/parser.py
+++ b/lib/yaml/parser.py
@@ -61,21 +61,21 @@
 
 __all__ = ['Parser', 'ParserError']
 
-from error import MarkedYAMLError
-from tokens import *
-from events import *
-from scanner import *
+from .error import MarkedYAMLError
+from .tokens import *
+from .events import *
+from .scanner import *
 
 class ParserError(MarkedYAMLError):
     pass
 
-class Parser(object):
+class Parser:
     # Since writing a recursive-descendant parser is a straightforward task, we
     # do not give many comments here.
 
     DEFAULT_TAGS = {
-        u'!':   u'!',
-        u'!!':  u'tag:yaml.org,2002:',
+        '!':   '!',
+        '!!':  'tag:yaml.org,2002:',
     }
 
     def __init__(self):
@@ -219,7 +219,7 @@
         self.tag_handles = {}
         while self.check_token(DirectiveToken):
             token = self.get_token()
-            if token.name == u'YAML':
+            if token.name == 'YAML':
                 if self.yaml_version is not None:
                     raise ParserError(None, None,
                             "found duplicate YAML directive", token.start_mark)
@@ -229,11 +229,11 @@
                             "found incompatible YAML document (version 1.* is required)",
                             token.start_mark)
                 self.yaml_version = token.value
-            elif token.name == u'TAG':
+            elif token.name == 'TAG':
                 handle, prefix = token.value
                 if handle in self.tag_handles:
                     raise ParserError(None, None,
-                            "duplicate tag handle %r" % handle.encode('utf-8'),
+                            "duplicate tag handle %r" % handle,
                             token.start_mark)
                 self.tag_handles[handle] = prefix
         if self.tag_handles:
@@ -303,19 +303,19 @@
                 if handle is not None:
                     if handle not in self.tag_handles:
                         raise ParserError("while parsing a node", start_mark,
-                                "found undefined tag handle %r" % handle.encode('utf-8'),
+                                "found undefined tag handle %r" % handle,
                                 tag_mark)
                     tag = self.tag_handles[handle]+suffix
                 else:
                     tag = suffix
-            #if tag == u'!':
+            #if tag == '!':
             #    raise ParserError("while parsing a node", start_mark,
             #            "found non-specific tag '!'", tag_mark,
             #            "Please check 'http://pyyaml.org/wiki/YAMLNonSpecificTag' and share your opinion.")
             if start_mark is None:
                 start_mark = end_mark = self.peek_token().start_mark
             event = None
-            implicit = (tag is None or tag == u'!')
+            implicit = (tag is None or tag == '!')
             if indentless_sequence and self.check_token(BlockEntryToken):
                 end_mark = self.peek_token().end_mark
                 event = SequenceStartEvent(anchor, tag, implicit,
@@ -325,7 +325,7 @@
                 if self.check_token(ScalarToken):
                     token = self.get_token()
                     end_mark = token.end_mark
-                    if (token.plain and tag is None) or tag == u'!':
+                    if (token.plain and tag is None) or tag == '!':
                         implicit = (True, False)
                     elif tag is None:
                         implicit = (False, True)
@@ -357,7 +357,7 @@
                 elif anchor is not None or tag is not None:
                     # Empty scalars are allowed even if a tag or an anchor is
                     # specified.
-                    event = ScalarEvent(anchor, tag, (implicit, False), u'',
+                    event = ScalarEvent(anchor, tag, (implicit, False), '',
                             start_mark, end_mark)
                     self.state = self.states.pop()
                 else:
@@ -585,5 +585,5 @@
         return self.process_empty_scalar(self.peek_token().start_mark)
 
     def process_empty_scalar(self, mark):
-        return ScalarEvent(None, None, (True, False), u'', mark, mark)
+        return ScalarEvent(None, None, (True, False), '', mark, mark)
 
diff --git a/lib/yaml/reader.py b/lib/yaml/reader.py
index 56a12f4..774b021 100644
--- a/lib/yaml/reader.py
+++ b/lib/yaml/reader.py
@@ -17,11 +17,9 @@
 
 __all__ = ['Reader', 'ReaderError']
 
-from error import YAMLError, Mark
+from .error import YAMLError, Mark
 
-import codecs, re, sys
-
-has_ucs4 = sys.maxunicode > 0xffff
+import codecs, re
 
 class ReaderError(YAMLError):
 
@@ -33,7 +31,7 @@
         self.reason = reason
 
     def __str__(self):
-        if isinstance(self.character, str):
+        if isinstance(self.character, bytes):
             return "'%s' codec can't decode byte #x%02x: %s\n"  \
                     "  in \"%s\", position %d"    \
                     % (self.encoding, ord(self.character), self.reason,
@@ -46,13 +44,13 @@
 
 class Reader(object):
     # Reader:
-    # - determines the data encoding and converts it to unicode,
+    # - determines the data encoding and converts it to a unicode string,
     # - checks if characters are in allowed range,
     # - adds '\0' to the end.
 
     # Reader accepts
+    #  - a `bytes` object,
     #  - a `str` object,
-    #  - a `unicode` object,
     #  - a file-like object with its `read` method returning `str`,
     #  - a file-like object with its `read` method returning `unicode`.
 
@@ -63,7 +61,7 @@
         self.stream = None
         self.stream_pointer = 0
         self.eof = True
-        self.buffer = u''
+        self.buffer = ''
         self.pointer = 0
         self.raw_buffer = None
         self.raw_decode = None
@@ -71,19 +69,19 @@
         self.index = 0
         self.line = 0
         self.column = 0
-        if isinstance(stream, unicode):
+        if isinstance(stream, str):
             self.name = "<unicode string>"
             self.check_printable(stream)
-            self.buffer = stream+u'\0'
-        elif isinstance(stream, str):
-            self.name = "<string>"
+            self.buffer = stream+'\0'
+        elif isinstance(stream, bytes):
+            self.name = "<byte string>"
             self.raw_buffer = stream
             self.determine_encoding()
         else:
             self.stream = stream
             self.name = getattr(stream, 'name', "<file>")
             self.eof = False
-            self.raw_buffer = ''
+            self.raw_buffer = None
             self.determine_encoding()
 
     def peek(self, index=0):
@@ -105,11 +103,11 @@
             ch = self.buffer[self.pointer]
             self.pointer += 1
             self.index += 1
-            if ch in u'\n\x85\u2028\u2029'  \
-                    or (ch == u'\r' and self.buffer[self.pointer] != u'\n'):
+            if ch in '\n\x85\u2028\u2029'  \
+                    or (ch == '\r' and self.buffer[self.pointer] != '\n'):
                 self.line += 1
                 self.column = 0
-            elif ch != u'\uFEFF':
+            elif ch != '\uFEFF':
                 self.column += 1
             length -= 1
 
@@ -122,9 +120,9 @@
                     None, None)
 
     def determine_encoding(self):
-        while not self.eof and len(self.raw_buffer) < 2:
+        while not self.eof and (self.raw_buffer is None or len(self.raw_buffer) < 2):
             self.update_raw()
-        if not isinstance(self.raw_buffer, unicode):
+        if isinstance(self.raw_buffer, bytes):
             if self.raw_buffer.startswith(codecs.BOM_UTF16_LE):
                 self.raw_decode = codecs.utf_16_le_decode
                 self.encoding = 'utf-16-le'
@@ -136,10 +134,7 @@
                 self.encoding = 'utf-8'
         self.update(1)
 
-    if has_ucs4:
-        NON_PRINTABLE = re.compile(u'[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD\U00010000-\U0010ffff]')
-    else:
-        NON_PRINTABLE = re.compile(u'[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD]')
+    NON_PRINTABLE = re.compile('[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD\U00010000-\U0010ffff]')
     def check_printable(self, data):
         match = self.NON_PRINTABLE.search(data)
         if match:
@@ -160,8 +155,8 @@
                 try:
                     data, converted = self.raw_decode(self.raw_buffer,
                             'strict', self.eof)
-                except UnicodeDecodeError, exc:
-                    character = exc.object[exc.start]
+                except UnicodeDecodeError as exc:
+                    character = self.raw_buffer[exc.start]
                     if self.stream is not None:
                         position = self.stream_pointer-len(self.raw_buffer)+exc.start
                     else:
@@ -175,20 +170,16 @@
             self.buffer += data
             self.raw_buffer = self.raw_buffer[converted:]
             if self.eof:
-                self.buffer += u'\0'
+                self.buffer += '\0'
                 self.raw_buffer = None
                 break
 
-    def update_raw(self, size=1024):
+    def update_raw(self, size=4096):
         data = self.stream.read(size)
-        if data:
-            self.raw_buffer += data
-            self.stream_pointer += len(data)
+        if self.raw_buffer is None:
+            self.raw_buffer = data
         else:
+            self.raw_buffer += data
+        self.stream_pointer += len(data)
+        if not data:
             self.eof = True
-
-#try:
-#    import psyco
-#    psyco.bind(Reader)
-#except ImportError:
-#    pass
diff --git a/lib/yaml/representer.py b/lib/yaml/representer.py
index f249f08..808ca06 100644
--- a/lib/yaml/representer.py
+++ b/lib/yaml/representer.py
@@ -2,23 +2,22 @@
 __all__ = ['BaseRepresenter', 'SafeRepresenter', 'Representer',
     'RepresenterError']
 
-from error import *
-from nodes import *
+from .error import *
+from .nodes import *
 
-import datetime
-
-import sys, copy_reg, types
+import datetime, copyreg, types, base64, collections
 
 class RepresenterError(YAMLError):
     pass
 
-class BaseRepresenter(object):
+class BaseRepresenter:
 
     yaml_representers = {}
     yaml_multi_representers = {}
 
-    def __init__(self, default_style=None, default_flow_style=None):
+    def __init__(self, default_style=None, default_flow_style=False, sort_keys=True):
         self.default_style = default_style
+        self.sort_keys = sort_keys
         self.default_flow_style = default_flow_style
         self.represented_objects = {}
         self.object_keeper = []
@@ -31,12 +30,6 @@
         self.object_keeper = []
         self.alias_key = None
 
-    def get_classobj_bases(self, cls):
-        bases = [cls]
-        for base in cls.__bases__:
-            bases.extend(self.get_classobj_bases(base))
-        return bases
-
     def represent_data(self, data):
         if self.ignore_aliases(data):
             self.alias_key = None
@@ -51,8 +44,6 @@
             #self.represented_objects[alias_key] = None
             self.object_keeper.append(data)
         data_types = type(data).__mro__
-        if type(data) is types.InstanceType:
-            data_types = self.get_classobj_bases(data.__class__)+list(data_types)
         if data_types[0] in self.yaml_representers:
             node = self.yaml_representers[data_types[0]](self, data)
         else:
@@ -66,22 +57,22 @@
                 elif None in self.yaml_representers:
                     node = self.yaml_representers[None](self, data)
                 else:
-                    node = ScalarNode(None, unicode(data))
+                    node = ScalarNode(None, str(data))
         #if alias_key is not None:
         #    self.represented_objects[alias_key] = node
         return node
 
+    @classmethod
     def add_representer(cls, data_type, representer):
         if not 'yaml_representers' in cls.__dict__:
             cls.yaml_representers = cls.yaml_representers.copy()
         cls.yaml_representers[data_type] = representer
-    add_representer = classmethod(add_representer)
 
+    @classmethod
     def add_multi_representer(cls, data_type, representer):
         if not 'yaml_multi_representers' in cls.__dict__:
             cls.yaml_multi_representers = cls.yaml_multi_representers.copy()
         cls.yaml_multi_representers[data_type] = representer
-    add_multi_representer = classmethod(add_multi_representer)
 
     def represent_scalar(self, tag, value, style=None):
         if style is None:
@@ -116,8 +107,12 @@
             self.represented_objects[self.alias_key] = node
         best_style = True
         if hasattr(mapping, 'items'):
-            mapping = mapping.items()
-            mapping.sort()
+            mapping = list(mapping.items())
+            if self.sort_keys:
+                try:
+                    mapping = sorted(mapping)
+                except TypeError:
+                    pass
         for item_key, item_value in mapping:
             node_key = self.represent_data(item_key)
             node_value = self.represent_data(item_value)
@@ -143,44 +138,31 @@
             return True
         if isinstance(data, tuple) and data == ():
             return True
-        if isinstance(data, (str, unicode, bool, int, float)):
+        if isinstance(data, (str, bytes, bool, int, float)):
             return True
 
     def represent_none(self, data):
-        return self.represent_scalar(u'tag:yaml.org,2002:null',
-                u'null')
+        return self.represent_scalar('tag:yaml.org,2002:null', 'null')
 
     def represent_str(self, data):
-        tag = None
-        style = None
-        try:
-            data = unicode(data, 'ascii')
-            tag = u'tag:yaml.org,2002:str'
-        except UnicodeDecodeError:
-            try:
-                data = unicode(data, 'utf-8')
-                tag = u'tag:yaml.org,2002:str'
-            except UnicodeDecodeError:
-                data = data.encode('base64')
-                tag = u'tag:yaml.org,2002:binary'
-                style = '|'
-        return self.represent_scalar(tag, data, style=style)
+        return self.represent_scalar('tag:yaml.org,2002:str', data)
 
-    def represent_unicode(self, data):
-        return self.represent_scalar(u'tag:yaml.org,2002:str', data)
+    def represent_binary(self, data):
+        if hasattr(base64, 'encodebytes'):
+            data = base64.encodebytes(data).decode('ascii')
+        else:
+            data = base64.encodestring(data).decode('ascii')
+        return self.represent_scalar('tag:yaml.org,2002:binary', data, style='|')
 
     def represent_bool(self, data):
         if data:
-            value = u'true'
+            value = 'true'
         else:
-            value = u'false'
-        return self.represent_scalar(u'tag:yaml.org,2002:bool', value)
+            value = 'false'
+        return self.represent_scalar('tag:yaml.org,2002:bool', value)
 
     def represent_int(self, data):
-        return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
-
-    def represent_long(self, data):
-        return self.represent_scalar(u'tag:yaml.org,2002:int', unicode(data))
+        return self.represent_scalar('tag:yaml.org,2002:int', str(data))
 
     inf_value = 1e300
     while repr(inf_value) != repr(inf_value*inf_value):
@@ -188,13 +170,13 @@
 
     def represent_float(self, data):
         if data != data or (data == 0.0 and data == 1.0):
-            value = u'.nan'
+            value = '.nan'
         elif data == self.inf_value:
-            value = u'.inf'
+            value = '.inf'
         elif data == -self.inf_value:
-            value = u'-.inf'
+            value = '-.inf'
         else:
-            value = unicode(repr(data)).lower()
+            value = repr(data).lower()
             # Note that in some cases `repr(data)` represents a float number
             # without the decimal parts.  For instance:
             #   >>> repr(1e17)
@@ -202,9 +184,9 @@
             # Unfortunately, this is not a valid float representation according
             # to the definition of the `!!float` tag.  We fix this by adding
             # '.0' before the 'e' symbol.
-            if u'.' not in value and u'e' in value:
-                value = value.replace(u'e', u'.0e', 1)
-        return self.represent_scalar(u'tag:yaml.org,2002:float', value)
+            if '.' not in value and 'e' in value:
+                value = value.replace('e', '.0e', 1)
+        return self.represent_scalar('tag:yaml.org,2002:float', value)
 
     def represent_list(self, data):
         #pairs = (len(data) > 0 and isinstance(data, list))
@@ -214,7 +196,7 @@
         #            pairs = False
         #            break
         #if not pairs:
-            return self.represent_sequence(u'tag:yaml.org,2002:seq', data)
+            return self.represent_sequence('tag:yaml.org,2002:seq', data)
         #value = []
         #for item_key, item_value in data:
         #    value.append(self.represent_mapping(u'tag:yaml.org,2002:map',
@@ -222,21 +204,21 @@
         #return SequenceNode(u'tag:yaml.org,2002:pairs', value)
 
     def represent_dict(self, data):
-        return self.represent_mapping(u'tag:yaml.org,2002:map', data)
+        return self.represent_mapping('tag:yaml.org,2002:map', data)
 
     def represent_set(self, data):
         value = {}
         for key in data:
             value[key] = None
-        return self.represent_mapping(u'tag:yaml.org,2002:set', value)
+        return self.represent_mapping('tag:yaml.org,2002:set', value)
 
     def represent_date(self, data):
-        value = unicode(data.isoformat())
-        return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
+        value = data.isoformat()
+        return self.represent_scalar('tag:yaml.org,2002:timestamp', value)
 
     def represent_datetime(self, data):
-        value = unicode(data.isoformat(' '))
-        return self.represent_scalar(u'tag:yaml.org,2002:timestamp', value)
+        value = data.isoformat(' ')
+        return self.represent_scalar('tag:yaml.org,2002:timestamp', value)
 
     def represent_yaml_object(self, tag, data, cls, flow_style=None):
         if hasattr(data, '__getstate__'):
@@ -254,8 +236,8 @@
 SafeRepresenter.add_representer(str,
         SafeRepresenter.represent_str)
 
-SafeRepresenter.add_representer(unicode,
-        SafeRepresenter.represent_unicode)
+SafeRepresenter.add_representer(bytes,
+        SafeRepresenter.represent_binary)
 
 SafeRepresenter.add_representer(bool,
         SafeRepresenter.represent_bool)
@@ -263,9 +245,6 @@
 SafeRepresenter.add_representer(int,
         SafeRepresenter.represent_int)
 
-SafeRepresenter.add_representer(long,
-        SafeRepresenter.represent_long)
-
 SafeRepresenter.add_representer(float,
         SafeRepresenter.represent_float)
 
@@ -292,99 +271,27 @@
 
 class Representer(SafeRepresenter):
 
-    def represent_str(self, data):
-        tag = None
-        style = None
-        try:
-            data = unicode(data, 'ascii')
-            tag = u'tag:yaml.org,2002:str'
-        except UnicodeDecodeError:
-            try:
-                data = unicode(data, 'utf-8')
-                tag = u'tag:yaml.org,2002:python/str'
-            except UnicodeDecodeError:
-                data = data.encode('base64')
-                tag = u'tag:yaml.org,2002:binary'
-                style = '|'
-        return self.represent_scalar(tag, data, style=style)
-
-    def represent_unicode(self, data):
-        tag = None
-        try:
-            data.encode('ascii')
-            tag = u'tag:yaml.org,2002:python/unicode'
-        except UnicodeEncodeError:
-            tag = u'tag:yaml.org,2002:str'
-        return self.represent_scalar(tag, data)
-
-    def represent_long(self, data):
-        tag = u'tag:yaml.org,2002:int'
-        if int(data) is not data:
-            tag = u'tag:yaml.org,2002:python/long'
-        return self.represent_scalar(tag, unicode(data))
-
     def represent_complex(self, data):
         if data.imag == 0.0:
-            data = u'%r' % data.real
+            data = '%r' % data.real
         elif data.real == 0.0:
-            data = u'%rj' % data.imag
+            data = '%rj' % data.imag
         elif data.imag > 0:
-            data = u'%r+%rj' % (data.real, data.imag)
+            data = '%r+%rj' % (data.real, data.imag)
         else:
-            data = u'%r%rj' % (data.real, data.imag)
-        return self.represent_scalar(u'tag:yaml.org,2002:python/complex', data)
+            data = '%r%rj' % (data.real, data.imag)
+        return self.represent_scalar('tag:yaml.org,2002:python/complex', data)
 
     def represent_tuple(self, data):
-        return self.represent_sequence(u'tag:yaml.org,2002:python/tuple', data)
+        return self.represent_sequence('tag:yaml.org,2002:python/tuple', data)
 
     def represent_name(self, data):
-        name = u'%s.%s' % (data.__module__, data.__name__)
-        return self.represent_scalar(u'tag:yaml.org,2002:python/name:'+name, u'')
+        name = '%s.%s' % (data.__module__, data.__name__)
+        return self.represent_scalar('tag:yaml.org,2002:python/name:'+name, '')
 
     def represent_module(self, data):
         return self.represent_scalar(
-                u'tag:yaml.org,2002:python/module:'+data.__name__, u'')
-
-    def represent_instance(self, data):
-        # For instances of classic classes, we use __getinitargs__ and
-        # __getstate__ to serialize the data.
-
-        # If data.__getinitargs__ exists, the object must be reconstructed by
-        # calling cls(**args), where args is a tuple returned by
-        # __getinitargs__. Otherwise, the cls.__init__ method should never be
-        # called and the class instance is created by instantiating a trivial
-        # class and assigning to the instance's __class__ variable.
-
-        # If data.__getstate__ exists, it returns the state of the object.
-        # Otherwise, the state of the object is data.__dict__.
-
-        # We produce either a !!python/object or !!python/object/new node.
-        # If data.__getinitargs__ does not exist and state is a dictionary, we
-        # produce a !!python/object node . Otherwise we produce a
-        # !!python/object/new node.
-
-        cls = data.__class__
-        class_name = u'%s.%s' % (cls.__module__, cls.__name__)
-        args = None
-        state = None
-        if hasattr(data, '__getinitargs__'):
-            args = list(data.__getinitargs__())
-        if hasattr(data, '__getstate__'):
-            state = data.__getstate__()
-        else:
-            state = data.__dict__
-        if args is None and isinstance(state, dict):
-            return self.represent_mapping(
-                    u'tag:yaml.org,2002:python/object:'+class_name, state)
-        if isinstance(state, dict) and not state:
-            return self.represent_sequence(
-                    u'tag:yaml.org,2002:python/object/new:'+class_name, args)
-        value = {}
-        if args:
-            value['args'] = args
-        value['state'] = state
-        return self.represent_mapping(
-                u'tag:yaml.org,2002:python/object/new:'+class_name, value)
+                'tag:yaml.org,2002:python/module:'+data.__name__, '')
 
     def represent_object(self, data):
         # We use __reduce__ API to save the data. data.__reduce__ returns
@@ -404,8 +311,8 @@
         # !!python/object/apply node.
 
         cls = type(data)
-        if cls in copy_reg.dispatch_table:
-            reduce = copy_reg.dispatch_table[cls](data)
+        if cls in copyreg.dispatch_table:
+            reduce = copyreg.dispatch_table[cls](data)
         elif hasattr(data, '__reduce_ex__'):
             reduce = data.__reduce_ex__(2)
         elif hasattr(data, '__reduce__'):
@@ -424,16 +331,16 @@
         if function.__name__ == '__newobj__':
             function = args[0]
             args = args[1:]
-            tag = u'tag:yaml.org,2002:python/object/new:'
+            tag = 'tag:yaml.org,2002:python/object/new:'
             newobj = True
         else:
-            tag = u'tag:yaml.org,2002:python/object/apply:'
+            tag = 'tag:yaml.org,2002:python/object/apply:'
             newobj = False
-        function_name = u'%s.%s' % (function.__module__, function.__name__)
+        function_name = '%s.%s' % (function.__module__, function.__name__)
         if not args and not listitems and not dictitems \
                 and isinstance(state, dict) and newobj:
             return self.represent_mapping(
-                    u'tag:yaml.org,2002:python/object:'+function_name, state)
+                    'tag:yaml.org,2002:python/object:'+function_name, state)
         if not listitems and not dictitems  \
                 and isinstance(state, dict) and not state:
             return self.represent_sequence(tag+function_name, args)
@@ -448,14 +355,13 @@
             value['dictitems'] = dictitems
         return self.represent_mapping(tag+function_name, value)
 
-Representer.add_representer(str,
-        Representer.represent_str)
-
-Representer.add_representer(unicode,
-        Representer.represent_unicode)
-
-Representer.add_representer(long,
-        Representer.represent_long)
+    def represent_ordered_dict(self, data):
+        # Provide uniform representation across different Python versions.
+        data_type = type(data)
+        tag = 'tag:yaml.org,2002:python/object/apply:%s.%s' \
+                % (data_type.__module__, data_type.__name__)
+        items = [[key, value] for key, value in data.items()]
+        return self.represent_sequence(tag, [items])
 
 Representer.add_representer(complex,
         Representer.represent_complex)
@@ -463,11 +369,11 @@
 Representer.add_representer(tuple,
         Representer.represent_tuple)
 
-Representer.add_representer(type,
+Representer.add_multi_representer(type,
         Representer.represent_name)
 
-Representer.add_representer(types.ClassType,
-        Representer.represent_name)
+Representer.add_representer(collections.OrderedDict,
+        Representer.represent_ordered_dict)
 
 Representer.add_representer(types.FunctionType,
         Representer.represent_name)
@@ -478,9 +384,6 @@
 Representer.add_representer(types.ModuleType,
         Representer.represent_module)
 
-Representer.add_multi_representer(types.InstanceType,
-        Representer.represent_instance)
-
 Representer.add_multi_representer(object,
         Representer.represent_object)
 
diff --git a/lib/yaml/resolver.py b/lib/yaml/resolver.py
index 528fbc0..3522bda 100644
--- a/lib/yaml/resolver.py
+++ b/lib/yaml/resolver.py
@@ -1,19 +1,19 @@
 
 __all__ = ['BaseResolver', 'Resolver']
 
-from error import *
-from nodes import *
+from .error import *
+from .nodes import *
 
 import re
 
 class ResolverError(YAMLError):
     pass
 
-class BaseResolver(object):
+class BaseResolver:
 
-    DEFAULT_SCALAR_TAG = u'tag:yaml.org,2002:str'
-    DEFAULT_SEQUENCE_TAG = u'tag:yaml.org,2002:seq'
-    DEFAULT_MAPPING_TAG = u'tag:yaml.org,2002:map'
+    DEFAULT_SCALAR_TAG = 'tag:yaml.org,2002:str'
+    DEFAULT_SEQUENCE_TAG = 'tag:yaml.org,2002:seq'
+    DEFAULT_MAPPING_TAG = 'tag:yaml.org,2002:map'
 
     yaml_implicit_resolvers = {}
     yaml_path_resolvers = {}
@@ -22,6 +22,7 @@
         self.resolver_exact_paths = []
         self.resolver_prefix_paths = []
 
+    @classmethod
     def add_implicit_resolver(cls, tag, regexp, first):
         if not 'yaml_implicit_resolvers' in cls.__dict__:
             implicit_resolvers = {}
@@ -32,8 +33,8 @@
             first = [None]
         for ch in first:
             cls.yaml_implicit_resolvers.setdefault(ch, []).append((tag, regexp))
-    add_implicit_resolver = classmethod(add_implicit_resolver)
 
+    @classmethod
     def add_path_resolver(cls, tag, path, kind=None):
         # Note: `add_path_resolver` is experimental.  The API could be changed.
         # `new_path` is a pattern that is matched against the path from the
@@ -69,10 +70,10 @@
             elif node_check is dict:
                 node_check = MappingNode
             elif node_check not in [ScalarNode, SequenceNode, MappingNode]  \
-                    and not isinstance(node_check, basestring)  \
+                    and not isinstance(node_check, str) \
                     and node_check is not None:
                 raise ResolverError("Invalid node checker: %s" % node_check)
-            if not isinstance(index_check, (basestring, int))   \
+            if not isinstance(index_check, (str, int))  \
                     and index_check is not None:
                 raise ResolverError("Invalid index checker: %s" % index_check)
             new_path.append((node_check, index_check))
@@ -86,7 +87,6 @@
                 and kind is not None:
             raise ResolverError("Invalid node kind: %s" % kind)
         cls.yaml_path_resolvers[tuple(new_path), kind] = tag
-    add_path_resolver = classmethod(add_path_resolver)
 
     def descend_resolver(self, current_node, current_index):
         if not self.yaml_path_resolvers:
@@ -120,7 +120,7 @@
     def check_resolver_prefix(self, depth, path, kind,
             current_node, current_index):
         node_check, index_check = path[depth-1]
-        if isinstance(node_check, basestring):
+        if isinstance(node_check, str):
             if current_node.tag != node_check:
                 return
         elif node_check is not None:
@@ -131,7 +131,7 @@
         if (index_check is False or index_check is None)    \
                 and current_index is None:
             return
-        if isinstance(index_check, basestring):
+        if isinstance(index_check, str):
             if not (isinstance(current_index, ScalarNode)
                     and index_check == current_index.value):
                 return
@@ -142,12 +142,12 @@
 
     def resolve(self, kind, value, implicit):
         if kind is ScalarNode and implicit[0]:
-            if value == u'':
-                resolvers = self.yaml_implicit_resolvers.get(u'', [])
+            if value == '':
+                resolvers = self.yaml_implicit_resolvers.get('', [])
             else:
                 resolvers = self.yaml_implicit_resolvers.get(value[0], [])
-            resolvers += self.yaml_implicit_resolvers.get(None, [])
-            for tag, regexp in resolvers:
+            wildcard_resolvers = self.yaml_implicit_resolvers.get(None, [])
+            for tag, regexp in resolvers + wildcard_resolvers:
                 if regexp.match(value):
                     return tag
             implicit = implicit[1]
@@ -168,60 +168,60 @@
     pass
 
 Resolver.add_implicit_resolver(
-        u'tag:yaml.org,2002:bool',
-        re.compile(ur'''^(?:yes|Yes|YES|no|No|NO
+        'tag:yaml.org,2002:bool',
+        re.compile(r'''^(?:yes|Yes|YES|no|No|NO
                     |true|True|TRUE|false|False|FALSE
                     |on|On|ON|off|Off|OFF)$''', re.X),
-        list(u'yYnNtTfFoO'))
+        list('yYnNtTfFoO'))
 
 Resolver.add_implicit_resolver(
-        u'tag:yaml.org,2002:float',
-        re.compile(ur'''^(?:[-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+][0-9]+)?
-                    |\.[0-9_]+(?:[eE][-+][0-9]+)?
+        'tag:yaml.org,2002:float',
+        re.compile(r'''^(?:[-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+][0-9]+)?
+                    |\.[0-9][0-9_]*(?:[eE][-+][0-9]+)?
                     |[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+\.[0-9_]*
                     |[-+]?\.(?:inf|Inf|INF)
                     |\.(?:nan|NaN|NAN))$''', re.X),
-        list(u'-+0123456789.'))
+        list('-+0123456789.'))
 
 Resolver.add_implicit_resolver(
-        u'tag:yaml.org,2002:int',
-        re.compile(ur'''^(?:[-+]?0b[0-1_]+
+        'tag:yaml.org,2002:int',
+        re.compile(r'''^(?:[-+]?0b[0-1_]+
                     |[-+]?0[0-7_]+
                     |[-+]?(?:0|[1-9][0-9_]*)
                     |[-+]?0x[0-9a-fA-F_]+
                     |[-+]?[1-9][0-9_]*(?::[0-5]?[0-9])+)$''', re.X),
-        list(u'-+0123456789'))
+        list('-+0123456789'))
 
 Resolver.add_implicit_resolver(
-        u'tag:yaml.org,2002:merge',
-        re.compile(ur'^(?:<<)$'),
-        [u'<'])
+        'tag:yaml.org,2002:merge',
+        re.compile(r'^(?:<<)$'),
+        ['<'])
 
 Resolver.add_implicit_resolver(
-        u'tag:yaml.org,2002:null',
-        re.compile(ur'''^(?: ~
+        'tag:yaml.org,2002:null',
+        re.compile(r'''^(?: ~
                     |null|Null|NULL
                     | )$''', re.X),
-        [u'~', u'n', u'N', u''])
+        ['~', 'n', 'N', ''])
 
 Resolver.add_implicit_resolver(
-        u'tag:yaml.org,2002:timestamp',
-        re.compile(ur'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
+        'tag:yaml.org,2002:timestamp',
+        re.compile(r'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
                     |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
                      (?:[Tt]|[ \t]+)[0-9][0-9]?
                      :[0-9][0-9] :[0-9][0-9] (?:\.[0-9]*)?
                      (?:[ \t]*(?:Z|[-+][0-9][0-9]?(?::[0-9][0-9])?))?)$''', re.X),
-        list(u'0123456789'))
+        list('0123456789'))
 
 Resolver.add_implicit_resolver(
-        u'tag:yaml.org,2002:value',
-        re.compile(ur'^(?:=)$'),
-        [u'='])
+        'tag:yaml.org,2002:value',
+        re.compile(r'^(?:=)$'),
+        ['='])
 
 # The following resolver is only for documentation purposes. It cannot work
 # because plain scalars cannot start with '!', '&', or '*'.
 Resolver.add_implicit_resolver(
-        u'tag:yaml.org,2002:yaml',
-        re.compile(ur'^(?:!|&|\*)$'),
-        list(u'!&*'))
+        'tag:yaml.org,2002:yaml',
+        re.compile(r'^(?:!|&|\*)$'),
+        list('!&*'))
 
diff --git a/lib/yaml/scanner.py b/lib/yaml/scanner.py
index f86cb80..de925b0 100644
--- a/lib/yaml/scanner.py
+++ b/lib/yaml/scanner.py
@@ -26,13 +26,13 @@
 
 __all__ = ['Scanner', 'ScannerError']
 
-from error import MarkedYAMLError
-from tokens import *
+from .error import MarkedYAMLError
+from .tokens import *
 
 class ScannerError(MarkedYAMLError):
     pass
 
-class SimpleKey(object):
+class SimpleKey:
     # See below simple keys treatment.
 
     def __init__(self, token_number, required, index, line, column, mark):
@@ -43,7 +43,7 @@
         self.column = column
         self.mark = mark
 
-class Scanner(object):
+class Scanner:
 
     def __init__(self):
         """Initialize the scanner."""
@@ -124,10 +124,13 @@
 
     def peek_token(self):
         # Return the next token, but do not delete if from the queue.
+        # Return None if no more tokens.
         while self.need_more_tokens():
             self.fetch_more_tokens()
         if self.tokens:
             return self.tokens[0]
+        else:
+            return None
 
     def get_token(self):
         # Return the next token.
@@ -166,85 +169,85 @@
         ch = self.peek()
 
         # Is it the end of stream?
-        if ch == u'\0':
+        if ch == '\0':
             return self.fetch_stream_end()
 
         # Is it a directive?
-        if ch == u'%' and self.check_directive():
+        if ch == '%' and self.check_directive():
             return self.fetch_directive()
 
         # Is it the document start?
-        if ch == u'-' and self.check_document_start():
+        if ch == '-' and self.check_document_start():
             return self.fetch_document_start()
 
         # Is it the document end?
-        if ch == u'.' and self.check_document_end():
+        if ch == '.' and self.check_document_end():
             return self.fetch_document_end()
 
         # TODO: support for BOM within a stream.
-        #if ch == u'\uFEFF':
+        #if ch == '\uFEFF':
         #    return self.fetch_bom()    <-- issue BOMToken
 
         # Note: the order of the following checks is NOT significant.
 
         # Is it the flow sequence start indicator?
-        if ch == u'[':
+        if ch == '[':
             return self.fetch_flow_sequence_start()
 
         # Is it the flow mapping start indicator?
-        if ch == u'{':
+        if ch == '{':
             return self.fetch_flow_mapping_start()
 
         # Is it the flow sequence end indicator?
-        if ch == u']':
+        if ch == ']':
             return self.fetch_flow_sequence_end()
 
         # Is it the flow mapping end indicator?
-        if ch == u'}':
+        if ch == '}':
             return self.fetch_flow_mapping_end()
 
         # Is it the flow entry indicator?
-        if ch == u',':
+        if ch == ',':
             return self.fetch_flow_entry()
 
         # Is it the block entry indicator?
-        if ch == u'-' and self.check_block_entry():
+        if ch == '-' and self.check_block_entry():
             return self.fetch_block_entry()
 
         # Is it the key indicator?
-        if ch == u'?' and self.check_key():
+        if ch == '?' and self.check_key():
             return self.fetch_key()
 
         # Is it the value indicator?
-        if ch == u':' and self.check_value():
+        if ch == ':' and self.check_value():
             return self.fetch_value()
 
         # Is it an alias?
-        if ch == u'*':
+        if ch == '*':
             return self.fetch_alias()
 
         # Is it an anchor?
-        if ch == u'&':
+        if ch == '&':
             return self.fetch_anchor()
 
         # Is it a tag?
-        if ch == u'!':
+        if ch == '!':
             return self.fetch_tag()
 
         # Is it a literal scalar?
-        if ch == u'|' and not self.flow_level:
+        if ch == '|' and not self.flow_level:
             return self.fetch_literal()
 
         # Is it a folded scalar?
-        if ch == u'>' and not self.flow_level:
+        if ch == '>' and not self.flow_level:
             return self.fetch_folded()
 
         # Is it a single quoted scalar?
-        if ch == u'\'':
+        if ch == '\'':
             return self.fetch_single()
 
         # Is it a double quoted scalar?
-        if ch == u'\"':
+        if ch == '\"':
             return self.fetch_double()
 
         # It must be a plain scalar then.
@@ -253,8 +256,8 @@
 
         # No? It's an error. Let's produce a nice error message.
         raise ScannerError("while scanning for the next token", None,
-                "found character %r that cannot start any token"
-                % ch.encode('utf-8'), self.get_mark())
+                "found character %r that cannot start any token" % ch,
+                self.get_mark())
 
     # Simple keys treatment.
 
@@ -280,7 +283,7 @@
         # - should be no longer than 1024 characters.
         # Disabling this procedure will allow simple keys of any length and
         # height (may cause problems if indentation is broken though).
-        for level in self.possible_simple_keys.keys():
+        for level in list(self.possible_simple_keys):
             key = self.possible_simple_keys[level]
             if key.line != self.line  \
                     or self.index-key.index > 1024:
@@ -329,7 +332,7 @@
         ## }
         #if self.flow_level and self.indent > column:
         #    raise ScannerError(None, None,
-        #            "invalid intendation or unclosed '[' or '{'",
+        #            "invalid indentation or unclosed '[' or '{'",
         #            self.get_mark())
 
         # In the flow context, indentation is ignored. We make the scanner less
@@ -367,7 +370,7 @@
 
     def fetch_stream_end(self):
 
-        # Set the current intendation to -1.
+        # Set the current indentation to -1.
         self.unwind_indent(-1)
 
         # Reset simple keys.
@@ -386,7 +389,7 @@
 
     def fetch_directive(self):
         
-        # Set the current intendation to -1.
+        # Set the current indentation to -1.
         self.unwind_indent(-1)
 
         # Reset simple keys.
@@ -404,7 +407,7 @@
 
     def fetch_document_indicator(self, TokenClass):
 
-        # Set the current intendation to -1.
+        # Set the current indentation to -1.
         self.unwind_indent(-1)
 
         # Reset simple keys. Note that there could not be a block collection
@@ -688,22 +691,22 @@
 
         # DOCUMENT-START:   ^ '---' (' '|'\n')
         if self.column == 0:
-            if self.prefix(3) == u'---'  \
-                    and self.peek(3) in u'\0 \t\r\n\x85\u2028\u2029':
+            if self.prefix(3) == '---'  \
+                    and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
                 return True
 
     def check_document_end(self):
 
         # DOCUMENT-END:     ^ '...' (' '|'\n')
         if self.column == 0:
-            if self.prefix(3) == u'...'  \
-                    and self.peek(3) in u'\0 \t\r\n\x85\u2028\u2029':
+            if self.prefix(3) == '...'  \
+                    and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
                 return True
 
     def check_block_entry(self):
 
         # BLOCK-ENTRY:      '-' (' '|'\n')
-        return self.peek(1) in u'\0 \t\r\n\x85\u2028\u2029'
+        return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
 
     def check_key(self):
 
@@ -713,7 +716,7 @@
 
         # KEY(block context):   '?' (' '|'\n')
         else:
-            return self.peek(1) in u'\0 \t\r\n\x85\u2028\u2029'
+            return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
 
     def check_value(self):
 
@@ -723,7 +726,7 @@
 
         # VALUE(block context): ':' (' '|'\n')
         else:
-            return self.peek(1) in u'\0 \t\r\n\x85\u2028\u2029'
+            return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
 
     def check_plain(self):
 
@@ -740,9 +743,9 @@
         # '-' character) because we want the flow context to be space
         # independent.
         ch = self.peek()
-        return ch not in u'\0 \t\r\n\x85\u2028\u2029-?:,[]{}#&*!|>\'\"%@`'  \
-                or (self.peek(1) not in u'\0 \t\r\n\x85\u2028\u2029'
-                        and (ch == u'-' or (not self.flow_level and ch in u'?:')))
+        return ch not in '\0 \t\r\n\x85\u2028\u2029-?:,[]{}#&*!|>\'\"%@`'  \
+                or (self.peek(1) not in '\0 \t\r\n\x85\u2028\u2029'
+                        and (ch == '-' or (not self.flow_level and ch in '?:')))
 
     # Scanners.
 
@@ -766,14 +769,14 @@
         # `unwind_indent` before issuing BLOCK-END.
         # Scanners for block, flow, and plain scalars need to be modified.
 
-        if self.index == 0 and self.peek() == u'\uFEFF':
+        if self.index == 0 and self.peek() == '\uFEFF':
             self.forward()
         found = False
         while not found:
-            while self.peek() == u' ':
+            while self.peek() == ' ':
                 self.forward()
-            if self.peek() == u'#':
-                while self.peek() not in u'\0\r\n\x85\u2028\u2029':
+            if self.peek() == '#':
+                while self.peek() not in '\0\r\n\x85\u2028\u2029':
                     self.forward()
             if self.scan_line_break():
                 if not self.flow_level:
@@ -787,15 +790,15 @@
         self.forward()
         name = self.scan_directive_name(start_mark)
         value = None
-        if name == u'YAML':
+        if name == 'YAML':
             value = self.scan_yaml_directive_value(start_mark)
             end_mark = self.get_mark()
-        elif name == u'TAG':
+        elif name == 'TAG':
             value = self.scan_tag_directive_value(start_mark)
             end_mark = self.get_mark()
         else:
             end_mark = self.get_mark()
-            while self.peek() not in u'\0\r\n\x85\u2028\u2029':
+            while self.peek() not in '\0\r\n\x85\u2028\u2029':
                 self.forward()
         self.scan_directive_ignored_line(start_mark)
         return DirectiveToken(name, value, start_mark, end_mark)
@@ -804,51 +807,48 @@
         # See the specification for details.
         length = 0
         ch = self.peek(length)
-        while u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z'    \
-                or ch in u'-_':
+        while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'  \
+                or ch in '-_':
             length += 1
             ch = self.peek(length)
         if not length:
             raise ScannerError("while scanning a directive", start_mark,
                     "expected alphabetic or numeric character, but found %r"
-                    % ch.encode('utf-8'), self.get_mark())
+                    % ch, self.get_mark())
         value = self.prefix(length)
         self.forward(length)
         ch = self.peek()
-        if ch not in u'\0 \r\n\x85\u2028\u2029':
+        if ch not in '\0 \r\n\x85\u2028\u2029':
             raise ScannerError("while scanning a directive", start_mark,
                     "expected alphabetic or numeric character, but found %r"
-                    % ch.encode('utf-8'), self.get_mark())
+                    % ch, self.get_mark())
         return value
 
     def scan_yaml_directive_value(self, start_mark):
         # See the specification for details.
-        while self.peek() == u' ':
+        while self.peek() == ' ':
             self.forward()
         major = self.scan_yaml_directive_number(start_mark)
         if self.peek() != '.':
             raise ScannerError("while scanning a directive", start_mark,
-                    "expected a digit or '.', but found %r"
-                    % self.peek().encode('utf-8'),
+                    "expected a digit or '.', but found %r" % self.peek(),
                     self.get_mark())
         self.forward()
         minor = self.scan_yaml_directive_number(start_mark)
-        if self.peek() not in u'\0 \r\n\x85\u2028\u2029':
+        if self.peek() not in '\0 \r\n\x85\u2028\u2029':
             raise ScannerError("while scanning a directive", start_mark,
-                    "expected a digit or ' ', but found %r"
-                    % self.peek().encode('utf-8'),
+                    "expected a digit or ' ', but found %r" % self.peek(),
                     self.get_mark())
         return (major, minor)
 
     def scan_yaml_directive_number(self, start_mark):
         # See the specification for details.
         ch = self.peek()
-        if not (u'0' <= ch <= u'9'):
+        if not ('0' <= ch <= '9'):
             raise ScannerError("while scanning a directive", start_mark,
-                    "expected a digit, but found %r" % ch.encode('utf-8'),
-                    self.get_mark())
+                    "expected a digit, but found %r" % ch, self.get_mark())
         length = 0
-        while u'0' <= self.peek(length) <= u'9':
+        while '0' <= self.peek(length) <= '9':
             length += 1
         value = int(self.prefix(length))
         self.forward(length)
@@ -856,10 +856,10 @@
 
     def scan_tag_directive_value(self, start_mark):
         # See the specification for details.
-        while self.peek() == u' ':
+        while self.peek() == ' ':
             self.forward()
         handle = self.scan_tag_directive_handle(start_mark)
-        while self.peek() == u' ':
+        while self.peek() == ' ':
             self.forward()
         prefix = self.scan_tag_directive_prefix(start_mark)
         return (handle, prefix)
@@ -868,34 +868,32 @@
         # See the specification for details.
         value = self.scan_tag_handle('directive', start_mark)
         ch = self.peek()
-        if ch != u' ':
+        if ch != ' ':
             raise ScannerError("while scanning a directive", start_mark,
-                    "expected ' ', but found %r" % ch.encode('utf-8'),
-                    self.get_mark())
+                    "expected ' ', but found %r" % ch, self.get_mark())
         return value
 
     def scan_tag_directive_prefix(self, start_mark):
         # See the specification for details.
         value = self.scan_tag_uri('directive', start_mark)
         ch = self.peek()
-        if ch not in u'\0 \r\n\x85\u2028\u2029':
+        if ch not in '\0 \r\n\x85\u2028\u2029':
             raise ScannerError("while scanning a directive", start_mark,
-                    "expected ' ', but found %r" % ch.encode('utf-8'),
-                    self.get_mark())
+                    "expected ' ', but found %r" % ch, self.get_mark())
         return value
 
     def scan_directive_ignored_line(self, start_mark):
         # See the specification for details.
-        while self.peek() == u' ':
+        while self.peek() == ' ':
             self.forward()
-        if self.peek() == u'#':
-            while self.peek() not in u'\0\r\n\x85\u2028\u2029':
+        if self.peek() == '#':
+            while self.peek() not in '\0\r\n\x85\u2028\u2029':
                 self.forward()
         ch = self.peek()
-        if ch not in u'\0\r\n\x85\u2028\u2029':
+        if ch not in '\0\r\n\x85\u2028\u2029':
             raise ScannerError("while scanning a directive", start_mark,
                     "expected a comment or a line break, but found %r"
-                        % ch.encode('utf-8'), self.get_mark())
+                        % ch, self.get_mark())
         self.scan_line_break()
 
     def scan_anchor(self, TokenClass):
@@ -909,28 +907,28 @@
         # Therefore we restrict aliases to numbers and ASCII letters.
         start_mark = self.get_mark()
         indicator = self.peek()
-        if indicator == u'*':
+        if indicator == '*':
             name = 'alias'
         else:
             name = 'anchor'
         self.forward()
         length = 0
         ch = self.peek(length)
-        while u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z'    \
-                or ch in u'-_':
+        while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'  \
+                or ch in '-_':
             length += 1
             ch = self.peek(length)
         if not length:
             raise ScannerError("while scanning an %s" % name, start_mark,
                     "expected alphabetic or numeric character, but found %r"
-                    % ch.encode('utf-8'), self.get_mark())
+                    % ch, self.get_mark())
         value = self.prefix(length)
         self.forward(length)
         ch = self.peek()
-        if ch not in u'\0 \t\r\n\x85\u2028\u2029?:,]}%@`':
+        if ch not in '\0 \t\r\n\x85\u2028\u2029?:,]}%@`':
             raise ScannerError("while scanning an %s" % name, start_mark,
                     "expected alphabetic or numeric character, but found %r"
-                    % ch.encode('utf-8'), self.get_mark())
+                    % ch, self.get_mark())
         end_mark = self.get_mark()
         return TokenClass(value, start_mark, end_mark)
 
@@ -938,40 +936,39 @@
         # See the specification for details.
         start_mark = self.get_mark()
         ch = self.peek(1)
-        if ch == u'<':
+        if ch == '<':
             handle = None
             self.forward(2)
             suffix = self.scan_tag_uri('tag', start_mark)
-            if self.peek() != u'>':
+            if self.peek() != '>':
                 raise ScannerError("while parsing a tag", start_mark,
-                        "expected '>', but found %r" % self.peek().encode('utf-8'),
+                        "expected '>', but found %r" % self.peek(),
                         self.get_mark())
             self.forward()
-        elif ch in u'\0 \t\r\n\x85\u2028\u2029':
+        elif ch in '\0 \t\r\n\x85\u2028\u2029':
             handle = None
-            suffix = u'!'
+            suffix = '!'
             self.forward()
         else:
             length = 1
             use_handle = False
-            while ch not in u'\0 \r\n\x85\u2028\u2029':
-                if ch == u'!':
+            while ch not in '\0 \r\n\x85\u2028\u2029':
+                if ch == '!':
                     use_handle = True
                     break
                 length += 1
                 ch = self.peek(length)
-            handle = u'!'
+            handle = '!'
             if use_handle:
                 handle = self.scan_tag_handle('tag', start_mark)
             else:
-                handle = u'!'
+                handle = '!'
                 self.forward()
             suffix = self.scan_tag_uri('tag', start_mark)
         ch = self.peek()
-        if ch not in u'\0 \r\n\x85\u2028\u2029':
+        if ch not in '\0 \r\n\x85\u2028\u2029':
             raise ScannerError("while scanning a tag", start_mark,
-                    "expected ' ', but found %r" % ch.encode('utf-8'),
-                    self.get_mark())
+                    "expected ' ', but found %r" % ch, self.get_mark())
         value = (handle, suffix)
         end_mark = self.get_mark()
         return TagToken(value, start_mark, end_mark)
@@ -1002,39 +999,39 @@
         else:
             indent = min_indent+increment-1
             breaks, end_mark = self.scan_block_scalar_breaks(indent)
-        line_break = u''
+        line_break = ''
 
         # Scan the inner part of the block scalar.
-        while self.column == indent and self.peek() != u'\0':
+        while self.column == indent and self.peek() != '\0':
             chunks.extend(breaks)
-            leading_non_space = self.peek() not in u' \t'
+            leading_non_space = self.peek() not in ' \t'
             length = 0
-            while self.peek(length) not in u'\0\r\n\x85\u2028\u2029':
+            while self.peek(length) not in '\0\r\n\x85\u2028\u2029':
                 length += 1
             chunks.append(self.prefix(length))
             self.forward(length)
             line_break = self.scan_line_break()
             breaks, end_mark = self.scan_block_scalar_breaks(indent)
-            if self.column == indent and self.peek() != u'\0':
+            if self.column == indent and self.peek() != '\0':
 
                 # Unfortunately, folding rules are ambiguous.
                 #
                 # This is the folding according to the specification:
                 
-                if folded and line_break == u'\n'   \
-                        and leading_non_space and self.peek() not in u' \t':
+                if folded and line_break == '\n'    \
+                        and leading_non_space and self.peek() not in ' \t':
                     if not breaks:
-                        chunks.append(u' ')
+                        chunks.append(' ')
                 else:
                     chunks.append(line_break)
                 
                 # This is Clark Evans's interpretation (also in the spec
                 # examples):
                 #
-                #if folded and line_break == u'\n':
+                #if folded and line_break == '\n':
                 #    if not breaks:
                 #        if self.peek() not in ' \t':
-                #            chunks.append(u' ')
+                #            chunks.append(' ')
                 #        else:
                 #            chunks.append(line_break)
                 #else:
@@ -1049,7 +1046,7 @@
             chunks.extend(breaks)
 
         # We are done.
-        return ScalarToken(u''.join(chunks), False, start_mark, end_mark,
+        return ScalarToken(''.join(chunks), False, start_mark, end_mark,
                 style)
 
     def scan_block_scalar_indicators(self, start_mark):
@@ -1057,21 +1054,21 @@
         chomping = None
         increment = None
         ch = self.peek()
-        if ch in u'+-':
+        if ch in '+-':
             if ch == '+':
                 chomping = True
             else:
                 chomping = False
             self.forward()
             ch = self.peek()
-            if ch in u'0123456789':
+            if ch in '0123456789':
                 increment = int(ch)
                 if increment == 0:
                     raise ScannerError("while scanning a block scalar", start_mark,
                             "expected indentation indicator in the range 1-9, but found 0",
                             self.get_mark())
                 self.forward()
-        elif ch in u'0123456789':
+        elif ch in '0123456789':
             increment = int(ch)
             if increment == 0:
                 raise ScannerError("while scanning a block scalar", start_mark,
@@ -1079,31 +1076,31 @@
                         self.get_mark())
             self.forward()
             ch = self.peek()
-            if ch in u'+-':
+            if ch in '+-':
                 if ch == '+':
                     chomping = True
                 else:
                     chomping = False
                 self.forward()
         ch = self.peek()
-        if ch not in u'\0 \r\n\x85\u2028\u2029':
+        if ch not in '\0 \r\n\x85\u2028\u2029':
             raise ScannerError("while scanning a block scalar", start_mark,
                     "expected chomping or indentation indicators, but found %r"
-                        % ch.encode('utf-8'), self.get_mark())
+                    % ch, self.get_mark())
         return chomping, increment
 
     def scan_block_scalar_ignored_line(self, start_mark):
         # See the specification for details.
-        while self.peek() == u' ':
+        while self.peek() == ' ':
             self.forward()
-        if self.peek() == u'#':
-            while self.peek() not in u'\0\r\n\x85\u2028\u2029':
+        if self.peek() == '#':
+            while self.peek() not in '\0\r\n\x85\u2028\u2029':
                 self.forward()
         ch = self.peek()
-        if ch not in u'\0\r\n\x85\u2028\u2029':
+        if ch not in '\0\r\n\x85\u2028\u2029':
             raise ScannerError("while scanning a block scalar", start_mark,
-                    "expected a comment or a line break, but found %r"
-                        % ch.encode('utf-8'), self.get_mark())
+                    "expected a comment or a line break, but found %r" % ch,
+                    self.get_mark())
         self.scan_line_break()
 
     def scan_block_scalar_indentation(self):
@@ -1111,8 +1108,8 @@
         chunks = []
         max_indent = 0
         end_mark = self.get_mark()
-        while self.peek() in u' \r\n\x85\u2028\u2029':
-            if self.peek() != u' ':
+        while self.peek() in ' \r\n\x85\u2028\u2029':
+            if self.peek() != ' ':
                 chunks.append(self.scan_line_break())
                 end_mark = self.get_mark()
             else:
@@ -1125,12 +1122,12 @@
         # See the specification for details.
         chunks = []
         end_mark = self.get_mark()
-        while self.column < indent and self.peek() == u' ':
+        while self.column < indent and self.peek() == ' ':
             self.forward()
-        while self.peek() in u'\r\n\x85\u2028\u2029':
+        while self.peek() in '\r\n\x85\u2028\u2029':
             chunks.append(self.scan_line_break())
             end_mark = self.get_mark()
-            while self.column < indent and self.peek() == u' ':
+            while self.column < indent and self.peek() == ' ':
                 self.forward()
         return chunks, end_mark
 
@@ -1155,33 +1152,34 @@
             chunks.extend(self.scan_flow_scalar_non_spaces(double, start_mark))
         self.forward()
         end_mark = self.get_mark()
-        return ScalarToken(u''.join(chunks), False, start_mark, end_mark,
+        return ScalarToken(''.join(chunks), False, start_mark, end_mark,
                 style)
 
     ESCAPE_REPLACEMENTS = {
-        u'0':   u'\0',
-        u'a':   u'\x07',
-        u'b':   u'\x08',
-        u't':   u'\x09',
-        u'\t':  u'\x09',
-        u'n':   u'\x0A',
-        u'v':   u'\x0B',
-        u'f':   u'\x0C',
-        u'r':   u'\x0D',
-        u'e':   u'\x1B',
-        u' ':   u'\x20',
-        u'\"':  u'\"',
-        u'\\':  u'\\',
-        u'N':   u'\x85',
-        u'_':   u'\xA0',
-        u'L':   u'\u2028',
-        u'P':   u'\u2029',
+        '0':    '\0',
+        'a':    '\x07',
+        'b':    '\x08',
+        't':    '\x09',
+        '\t':   '\x09',
+        'n':    '\x0A',
+        'v':    '\x0B',
+        'f':    '\x0C',
+        'r':    '\x0D',
+        'e':    '\x1B',
+        ' ':    '\x20',
+        '\"':   '\"',
+        '\\':   '\\',
+        '/':    '/',
+        'N':    '\x85',
+        '_':    '\xA0',
+        'L':    '\u2028',
+        'P':    '\u2029',
     }
 
     ESCAPE_CODES = {
-        u'x':   2,
-        u'u':   4,
-        u'U':   8,
+        'x':    2,
+        'u':    4,
+        'U':    8,
     }
 
     def scan_flow_scalar_non_spaces(self, double, start_mark):
@@ -1189,19 +1187,19 @@
         chunks = []
         while True:
             length = 0
-            while self.peek(length) not in u'\'\"\\\0 \t\r\n\x85\u2028\u2029':
+            while self.peek(length) not in '\'\"\\\0 \t\r\n\x85\u2028\u2029':
                 length += 1
             if length:
                 chunks.append(self.prefix(length))
                 self.forward(length)
             ch = self.peek()
-            if not double and ch == u'\'' and self.peek(1) == u'\'':
-                chunks.append(u'\'')
+            if not double and ch == '\'' and self.peek(1) == '\'':
+                chunks.append('\'')
                 self.forward(2)
-            elif (double and ch == u'\'') or (not double and ch in u'\"\\'):
+            elif (double and ch == '\'') or (not double and ch in '\"\\'):
                 chunks.append(ch)
                 self.forward()
-            elif double and ch == u'\\':
+            elif double and ch == '\\':
                 self.forward()
                 ch = self.peek()
                 if ch in self.ESCAPE_REPLACEMENTS:
@@ -1211,19 +1209,19 @@
                     length = self.ESCAPE_CODES[ch]
                     self.forward()
                     for k in range(length):
-                        if self.peek(k) not in u'0123456789ABCDEFabcdef':
+                        if self.peek(k) not in '0123456789ABCDEFabcdef':
                             raise ScannerError("while scanning a double-quoted scalar", start_mark,
-                                    "expected escape sequence of %d hexdecimal numbers, but found %r" %
-                                        (length, self.peek(k).encode('utf-8')), self.get_mark())
+                                    "expected escape sequence of %d hexadecimal numbers, but found %r" %
+                                        (length, self.peek(k)), self.get_mark())
                     code = int(self.prefix(length), 16)
-                    chunks.append(unichr(code))
+                    chunks.append(chr(code))
                     self.forward(length)
-                elif ch in u'\r\n\x85\u2028\u2029':
+                elif ch in '\r\n\x85\u2028\u2029':
                     self.scan_line_break()
                     chunks.extend(self.scan_flow_scalar_breaks(double, start_mark))
                 else:
                     raise ScannerError("while scanning a double-quoted scalar", start_mark,
-                            "found unknown escape character %r" % ch.encode('utf-8'), self.get_mark())
+                            "found unknown escape character %r" % ch, self.get_mark())
             else:
                 return chunks
 
@@ -1231,21 +1229,21 @@
         # See the specification for details.
         chunks = []
         length = 0
-        while self.peek(length) in u' \t':
+        while self.peek(length) in ' \t':
             length += 1
         whitespaces = self.prefix(length)
         self.forward(length)
         ch = self.peek()
-        if ch == u'\0':
+        if ch == '\0':
             raise ScannerError("while scanning a quoted scalar", start_mark,
                     "found unexpected end of stream", self.get_mark())
-        elif ch in u'\r\n\x85\u2028\u2029':
+        elif ch in '\r\n\x85\u2028\u2029':
             line_break = self.scan_line_break()
             breaks = self.scan_flow_scalar_breaks(double, start_mark)
-            if line_break != u'\n':
+            if line_break != '\n':
                 chunks.append(line_break)
             elif not breaks:
-                chunks.append(u' ')
+                chunks.append(' ')
             chunks.extend(breaks)
         else:
             chunks.append(whitespaces)
@@ -1258,13 +1256,13 @@
             # Instead of checking indentation, we check for document
             # separators.
             prefix = self.prefix(3)
-            if (prefix == u'---' or prefix == u'...')   \
-                    and self.peek(3) in u'\0 \t\r\n\x85\u2028\u2029':
+            if (prefix == '---' or prefix == '...')   \
+                    and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
                 raise ScannerError("while scanning a quoted scalar", start_mark,
                         "found unexpected document separator", self.get_mark())
-            while self.peek() in u' \t':
+            while self.peek() in ' \t':
                 self.forward()
-            if self.peek() in u'\r\n\x85\u2028\u2029':
+            if self.peek() in '\r\n\x85\u2028\u2029':
                 chunks.append(self.scan_line_break())
             else:
                 return chunks
@@ -1286,15 +1284,15 @@
         spaces = []
         while True:
             length = 0
-            if self.peek() == u'#':
+            if self.peek() == '#':
                 break
             while True:
                 ch = self.peek(length)
-                if ch in u'\0 \t\r\n\x85\u2028\u2029'   \
-                        or (ch == u':' and
-                                self.peek(length+1) in u'\0 \t\r\n\x85\u2028\u2029'
+                if ch in '\0 \t\r\n\x85\u2028\u2029'    \
+                        or (ch == ':' and
+                                self.peek(length+1) in '\0 \t\r\n\x85\u2028\u2029'
                                       + (u',[]{}' if self.flow_level else u''))\
-                        or (self.flow_level and ch in u',?[]{}'):
+                        or (self.flow_level and ch in ',?[]{}'):
                     break
                 length += 1
             if length == 0:
@@ -1305,10 +1303,10 @@
             self.forward(length)
             end_mark = self.get_mark()
             spaces = self.scan_plain_spaces(indent, start_mark)
-            if not spaces or self.peek() == u'#' \
+            if not spaces or self.peek() == '#' \
                     or (not self.flow_level and self.column < indent):
                 break
-        return ScalarToken(u''.join(chunks), True, start_mark, end_mark)
+        return ScalarToken(''.join(chunks), True, start_mark, end_mark)
 
     def scan_plain_spaces(self, indent, start_mark):
         # See the specification for details.
@@ -1316,32 +1314,32 @@
         # We just forbid them completely. Do not use tabs in YAML!
         chunks = []
         length = 0
-        while self.peek(length) in u' ':
+        while self.peek(length) in ' ':
             length += 1
         whitespaces = self.prefix(length)
         self.forward(length)
         ch = self.peek()
-        if ch in u'\r\n\x85\u2028\u2029':
+        if ch in '\r\n\x85\u2028\u2029':
             line_break = self.scan_line_break()
             self.allow_simple_key = True
             prefix = self.prefix(3)
-            if (prefix == u'---' or prefix == u'...')   \
-                    and self.peek(3) in u'\0 \t\r\n\x85\u2028\u2029':
+            if (prefix == '---' or prefix == '...')   \
+                    and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
                 return
             breaks = []
-            while self.peek() in u' \r\n\x85\u2028\u2029':
+            while self.peek() in ' \r\n\x85\u2028\u2029':
                 if self.peek() == ' ':
                     self.forward()
                 else:
                     breaks.append(self.scan_line_break())
                     prefix = self.prefix(3)
-                    if (prefix == u'---' or prefix == u'...')   \
-                            and self.peek(3) in u'\0 \t\r\n\x85\u2028\u2029':
+                    if (prefix == '---' or prefix == '...')   \
+                            and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
                         return
-            if line_break != u'\n':
+            if line_break != '\n':
                 chunks.append(line_break)
             elif not breaks:
-                chunks.append(u' ')
+                chunks.append(' ')
             chunks.extend(breaks)
         elif whitespaces:
             chunks.append(whitespaces)
@@ -1352,22 +1350,20 @@
         # For some strange reasons, the specification does not allow '_' in
         # tag handles. I have allowed it anyway.
         ch = self.peek()
-        if ch != u'!':
+        if ch != '!':
             raise ScannerError("while scanning a %s" % name, start_mark,
-                    "expected '!', but found %r" % ch.encode('utf-8'),
-                    self.get_mark())
+                    "expected '!', but found %r" % ch, self.get_mark())
         length = 1
         ch = self.peek(length)
-        if ch != u' ':
-            while u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z'    \
-                    or ch in u'-_':
+        if ch != ' ':
+            while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'  \
+                    or ch in '-_':
                 length += 1
                 ch = self.peek(length)
-            if ch != u'!':
+            if ch != '!':
                 self.forward(length)
                 raise ScannerError("while scanning a %s" % name, start_mark,
-                        "expected '!', but found %r" % ch.encode('utf-8'),
-                        self.get_mark())
+                        "expected '!', but found %r" % ch, self.get_mark())
             length += 1
         value = self.prefix(length)
         self.forward(length)
@@ -1379,9 +1375,9 @@
         chunks = []
         length = 0
         ch = self.peek(length)
-        while u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z'    \
-                or ch in u'-;/?:@&=+$,_.!~*\'()[]%':
-            if ch == u'%':
+        while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'  \
+                or ch in '-;/?:@&=+$,_.!~*\'()[]%':
+            if ch == '%':
                 chunks.append(self.prefix(length))
                 self.forward(length)
                 length = 0
@@ -1395,26 +1391,25 @@
             length = 0
         if not chunks:
             raise ScannerError("while parsing a %s" % name, start_mark,
-                    "expected URI, but found %r" % ch.encode('utf-8'),
-                    self.get_mark())
-        return u''.join(chunks)
+                    "expected URI, but found %r" % ch, self.get_mark())
+        return ''.join(chunks)
 
     def scan_uri_escapes(self, name, start_mark):
         # See the specification for details.
-        bytes = []
+        codes = []
         mark = self.get_mark()
-        while self.peek() == u'%':
+        while self.peek() == '%':
             self.forward()
             for k in range(2):
-                if self.peek(k) not in u'0123456789ABCDEFabcdef':
+                if self.peek(k) not in '0123456789ABCDEFabcdef':
                     raise ScannerError("while scanning a %s" % name, start_mark,
-                            "expected URI escape sequence of 2 hexdecimal numbers, but found %r" %
-                                (self.peek(k).encode('utf-8')), self.get_mark())
-            bytes.append(chr(int(self.prefix(2), 16)))
+                            "expected URI escape sequence of 2 hexadecimal numbers, but found %r"
+                            % self.peek(k), self.get_mark())
+            codes.append(int(self.prefix(2), 16))
             self.forward(2)
         try:
-            value = unicode(''.join(bytes), 'utf-8')
-        except UnicodeDecodeError, exc:
+            value = bytes(codes).decode('utf-8')
+        except UnicodeDecodeError as exc:
             raise ScannerError("while scanning a %s" % name, start_mark, str(exc), mark)
         return value
 
@@ -1428,20 +1423,13 @@
         #   '\u2029     :   '\u2029'
         #   default     :   ''
         ch = self.peek()
-        if ch in u'\r\n\x85':
-            if self.prefix(2) == u'\r\n':
+        if ch in '\r\n\x85':
+            if self.prefix(2) == '\r\n':
                 self.forward(2)
             else:
                 self.forward()
-            return u'\n'
-        elif ch in u'\u2028\u2029':
+            return '\n'
+        elif ch in '\u2028\u2029':
             self.forward()
             return ch
-        return u''
-
-#try:
-#    import psyco
-#    psyco.bind(Scanner)
-#except ImportError:
-#    pass
-
+        return ''
diff --git a/lib/yaml/serializer.py b/lib/yaml/serializer.py
index 0bf1e96..fe911e6 100644
--- a/lib/yaml/serializer.py
+++ b/lib/yaml/serializer.py
@@ -1,16 +1,16 @@
 
 __all__ = ['Serializer', 'SerializerError']
 
-from error import YAMLError
-from events import *
-from nodes import *
+from .error import YAMLError
+from .events import *
+from .nodes import *
 
 class SerializerError(YAMLError):
     pass
 
-class Serializer(object):
+class Serializer:
 
-    ANCHOR_TEMPLATE = u'id%03d'
+    ANCHOR_TEMPLATE = 'id%03d'
 
     def __init__(self, encoding=None,
             explicit_start=None, explicit_end=None, version=None, tags=None):
diff --git a/lib3/yaml/__init__.py b/lib3/yaml/__init__.py
deleted file mode 100644
index f79588c..0000000
--- a/lib3/yaml/__init__.py
+++ /dev/null
@@ -1,322 +0,0 @@
-
-from .error import *
-
-from .tokens import *
-from .events import *
-from .nodes import *
-
-from .loader import *
-from .dumper import *
-
-__version__ = '3.12'
-try:
-    from .cyaml import *
-    __with_libyaml__ = True
-except ImportError:
-    __with_libyaml__ = False
-
-import io
-
-def scan(stream, Loader=Loader):
-    """
-    Scan a YAML stream and produce scanning tokens.
-    """
-    loader = Loader(stream)
-    try:
-        while loader.check_token():
-            yield loader.get_token()
-    finally:
-        loader.dispose()
-
-def parse(stream, Loader=Loader):
-    """
-    Parse a YAML stream and produce parsing events.
-    """
-    loader = Loader(stream)
-    try:
-        while loader.check_event():
-            yield loader.get_event()
-    finally:
-        loader.dispose()
-
-def compose(stream, Loader=Loader):
-    """
-    Parse the first YAML document in a stream
-    and produce the corresponding representation tree.
-    """
-    loader = Loader(stream)
-    try:
-        return loader.get_single_node()
-    finally:
-        loader.dispose()
-
-def compose_all(stream, Loader=Loader):
-    """
-    Parse all YAML documents in a stream
-    and produce corresponding representation trees.
-    """
-    loader = Loader(stream)
-    try:
-        while loader.check_node():
-            yield loader.get_node()
-    finally:
-        loader.dispose()
-
-def load(stream, Loader=Loader):
-    """
-    Parse the first YAML document in a stream
-    and produce the corresponding Python object.
-
-    By default resolve only basic YAML tags, if an alternate Loader is
-    provided, may be dangerous.
-    """
-    loader = Loader(stream)
-    try:
-        return loader.get_single_data()
-    finally:
-        loader.dispose()
-safe_load = load
-
-def load_all(stream, Loader=Loader):
-    """
-    Parse all YAML documents in a stream
-    and produce corresponding Python objects.
-
-    By default resolve only basic YAML tags, if an alternate Loader is
-    provided, may be dangerous.
-    """
-    loader = Loader(stream)
-    try:
-        while loader.check_data():
-            yield loader.get_data()
-    finally:
-        loader.dispose()
-safe_load_all = load_all
-
-def danger_load(stream):
-    """
-    Parse the first YAML document in a stream
-    and produce the corresponding Python object.
-    When used on untrusted input, can result in arbitrary code execution.
-    """
-    return load(stream, DangerLoader)
-
-def danger_load_all(stream):
-    """
-    Parse all YAML documents in a stream
-    and produce corresponding Python objects.
-    When used on untrusted input, can result in arbitrary code execution.
-    """
-    return load_all(stream, DangerLoader)
-
-def emit(events, stream=None, Dumper=Dumper,
-        canonical=None, indent=None, width=None,
-        allow_unicode=None, line_break=None):
-    """
-    Emit YAML parsing events into a stream.
-    If stream is None, return the produced string instead.
-    """
-    getvalue = None
-    if stream is None:
-        stream = io.StringIO()
-        getvalue = stream.getvalue
-    dumper = Dumper(stream, canonical=canonical, indent=indent, width=width,
-            allow_unicode=allow_unicode, line_break=line_break)
-    try:
-        for event in events:
-            dumper.emit(event)
-    finally:
-        dumper.dispose()
-    if getvalue:
-        return getvalue()
-
-def serialize_all(nodes, stream=None, Dumper=Dumper,
-        canonical=None, indent=None, width=None,
-        allow_unicode=None, line_break=None,
-        encoding=None, explicit_start=None, explicit_end=None,
-        version=None, tags=None):
-    """
-    Serialize a sequence of representation trees into a YAML stream.
-    If stream is None, return the produced string instead.
-    """
-    getvalue = None
-    if stream is None:
-        if encoding is None:
-            stream = io.StringIO()
-        else:
-            stream = io.BytesIO()
-        getvalue = stream.getvalue
-    dumper = Dumper(stream, canonical=canonical, indent=indent, width=width,
-            allow_unicode=allow_unicode, line_break=line_break,
-            encoding=encoding, version=version, tags=tags,
-            explicit_start=explicit_start, explicit_end=explicit_end)
-    try:
-        dumper.open()
-        for node in nodes:
-            dumper.serialize(node)
-        dumper.close()
-    finally:
-        dumper.dispose()
-    if getvalue:
-        return getvalue()
-
-def serialize(node, stream=None, Dumper=Dumper, **kwds):
-    """
-    Serialize a representation tree into a YAML stream.
-    If stream is None, return the produced string instead.
-    """
-    return serialize_all([node], stream, Dumper=Dumper, **kwds)
-
-def dump_all(documents, stream=None, Dumper=Dumper,
-        default_style=None, default_flow_style=None,
-        canonical=None, indent=None, width=None,
-        allow_unicode=None, line_break=None,
-        encoding=None, explicit_start=None, explicit_end=None,
-        version=None, tags=None):
-    """
-    Serialize a sequence of Python objects into a YAML stream.
-    If stream is None, return the produced string instead.
-    """
-    getvalue = None
-    if stream is None:
-        if encoding is None:
-            stream = io.StringIO()
-        else:
-            stream = io.BytesIO()
-        getvalue = stream.getvalue
-    dumper = Dumper(stream, default_style=default_style,
-            default_flow_style=default_flow_style,
-            canonical=canonical, indent=indent, width=width,
-            allow_unicode=allow_unicode, line_break=line_break,
-            encoding=encoding, version=version, tags=tags,
-            explicit_start=explicit_start, explicit_end=explicit_end)
-    try:
-        dumper.open()
-        for data in documents:
-            dumper.represent(data)
-        dumper.close()
-    finally:
-        dumper.dispose()
-    if getvalue:
-        return getvalue()
-safe_dump_all = dump_all
-
-def danger_dump_all(documents, stream=None, **kwds):
-    """
-    Serialize a sequence of Python objects into a YAML stream.
-    Produce only basic YAML tags.
-    If stream is None, return the produced string instead.
-    """
-    return dump_all(documents, stream, Dumper=DangerDumper, **kwds)
-
-def dump(data, stream=None, Dumper=Dumper, **kwds):
-    """
-    Serialize a Python object into a YAML stream.
-    If stream is None, return the produced string instead.
-    """
-    return dump_all([data], stream, Dumper=Dumper, **kwds)
-safe_dump = dump
-
-def danger_dump(data, stream=None, **kwds):
-    """
-    Serialize a Python object into a YAML stream.
-    Produce only basic YAML tags.
-    If stream is None, return the produced string instead.
-    """
-    return dump_all([data], stream, Dumper=DangerDumper, **kwds)
-
-def add_implicit_resolver(tag, regexp, first=None,
-        Loader=Loader, Dumper=Dumper):
-    """
-    Add an implicit scalar detector.
-    If an implicit scalar value matches the given regexp,
-    the corresponding tag is assigned to the scalar.
-    first is a sequence of possible initial characters or None.
-    """
-    Loader.add_implicit_resolver(tag, regexp, first)
-    Dumper.add_implicit_resolver(tag, regexp, first)
-
-def add_path_resolver(tag, path, kind=None, Loader=Loader, Dumper=Dumper):
-    """
-    Add a path based resolver for the given tag.
-    A path is a list of keys that forms a path
-    to a node in the representation tree.
-    Keys can be string values, integers, or None.
-    """
-    Loader.add_path_resolver(tag, path, kind)
-    Dumper.add_path_resolver(tag, path, kind)
-
-def add_constructor(tag, constructor, Loader=Loader):
-    """
-    Add a constructor for the given tag.
-    Constructor is a function that accepts a Loader instance
-    and a node object and produces the corresponding Python object.
-    """
-    Loader.add_constructor(tag, constructor)
-
-def add_multi_constructor(tag_prefix, multi_constructor, Loader=Loader):
-    """
-    Add a multi-constructor for the given tag prefix.
-    Multi-constructor is called for a node if its tag starts with tag_prefix.
-    Multi-constructor accepts a Loader instance, a tag suffix,
-    and a node object and produces the corresponding Python object.
-    """
-    Loader.add_multi_constructor(tag_prefix, multi_constructor)
-
-def add_representer(data_type, representer, Dumper=Dumper):
-    """
-    Add a representer for the given type.
-    Representer is a function accepting a Dumper instance
-    and an instance of the given data type
-    and producing the corresponding representation node.
-    """
-    Dumper.add_representer(data_type, representer)
-
-def add_multi_representer(data_type, multi_representer, Dumper=Dumper):
-    """
-    Add a representer for the given type.
-    Multi-representer is a function accepting a Dumper instance
-    and an instance of the given data type or subtype
-    and producing the corresponding representation node.
-    """
-    Dumper.add_multi_representer(data_type, multi_representer)
-
-class YAMLObjectMetaclass(type):
-    """
-    The metaclass for YAMLObject.
-    """
-    def __init__(cls, name, bases, kwds):
-        super(YAMLObjectMetaclass, cls).__init__(name, bases, kwds)
-        if 'yaml_tag' in kwds and kwds['yaml_tag'] is not None:
-            cls.yaml_loader.add_constructor(cls.yaml_tag, cls.from_yaml)
-            cls.yaml_dumper.add_representer(cls, cls.to_yaml)
-
-class YAMLObject(metaclass=YAMLObjectMetaclass):
-    """
-    An object that can dump itself to a YAML stream
-    and load itself from a YAML stream.
-    """
-
-    __slots__ = ()  # no direct instantiation, so allow immutable subclasses
-
-    yaml_loader = Loader
-    yaml_dumper = Dumper
-
-    yaml_tag = None
-    yaml_flow_style = None
-
-    @classmethod
-    def from_yaml(cls, loader, node):
-        """
-        Convert a representation node to a Python object.
-        """
-        return loader.construct_yaml_object(node, cls)
-
-    @classmethod
-    def to_yaml(cls, dumper, data):
-        """
-        Convert a Python object to a representation node.
-        """
-        return dumper.represent_yaml_object(cls.yaml_tag, data, cls,
-                flow_style=cls.yaml_flow_style)
-
diff --git a/lib3/yaml/composer.py b/lib3/yaml/composer.py
deleted file mode 100644
index 6d15cb4..0000000
--- a/lib3/yaml/composer.py
+++ /dev/null
@@ -1,139 +0,0 @@
-
-__all__ = ['Composer', 'ComposerError']
-
-from .error import MarkedYAMLError
-from .events import *
-from .nodes import *
-
-class ComposerError(MarkedYAMLError):
-    pass
-
-class Composer:
-
-    def __init__(self):
-        self.anchors = {}
-
-    def check_node(self):
-        # Drop the STREAM-START event.
-        if self.check_event(StreamStartEvent):
-            self.get_event()
-
-        # If there are more documents available?
-        return not self.check_event(StreamEndEvent)
-
-    def get_node(self):
-        # Get the root node of the next document.
-        if not self.check_event(StreamEndEvent):
-            return self.compose_document()
-
-    def get_single_node(self):
-        # Drop the STREAM-START event.
-        self.get_event()
-
-        # Compose a document if the stream is not empty.
-        document = None
-        if not self.check_event(StreamEndEvent):
-            document = self.compose_document()
-
-        # Ensure that the stream contains no more documents.
-        if not self.check_event(StreamEndEvent):
-            event = self.get_event()
-            raise ComposerError("expected a single document in the stream",
-                    document.start_mark, "but found another document",
-                    event.start_mark)
-
-        # Drop the STREAM-END event.
-        self.get_event()
-
-        return document
-
-    def compose_document(self):
-        # Drop the DOCUMENT-START event.
-        self.get_event()
-
-        # Compose the root node.
-        node = self.compose_node(None, None)
-
-        # Drop the DOCUMENT-END event.
-        self.get_event()
-
-        self.anchors = {}
-        return node
-
-    def compose_node(self, parent, index):
-        if self.check_event(AliasEvent):
-            event = self.get_event()
-            anchor = event.anchor
-            if anchor not in self.anchors:
-                raise ComposerError(None, None, "found undefined alias %r"
-                        % anchor, event.start_mark)
-            return self.anchors[anchor]
-        event = self.peek_event()
-        anchor = event.anchor
-        if anchor is not None:
-            if anchor in self.anchors:
-                raise ComposerError("found duplicate anchor %r; first occurrence"
-                        % anchor, self.anchors[anchor].start_mark,
-                        "second occurrence", event.start_mark)
-        self.descend_resolver(parent, index)
-        if self.check_event(ScalarEvent):
-            node = self.compose_scalar_node(anchor)
-        elif self.check_event(SequenceStartEvent):
-            node = self.compose_sequence_node(anchor)
-        elif self.check_event(MappingStartEvent):
-            node = self.compose_mapping_node(anchor)
-        self.ascend_resolver()
-        return node
-
-    def compose_scalar_node(self, anchor):
-        event = self.get_event()
-        tag = event.tag
-        if tag is None or tag == '!':
-            tag = self.resolve(ScalarNode, event.value, event.implicit)
-        node = ScalarNode(tag, event.value,
-                event.start_mark, event.end_mark, style=event.style)
-        if anchor is not None:
-            self.anchors[anchor] = node
-        return node
-
-    def compose_sequence_node(self, anchor):
-        start_event = self.get_event()
-        tag = start_event.tag
-        if tag is None or tag == '!':
-            tag = self.resolve(SequenceNode, None, start_event.implicit)
-        node = SequenceNode(tag, [],
-                start_event.start_mark, None,
-                flow_style=start_event.flow_style)
-        if anchor is not None:
-            self.anchors[anchor] = node
-        index = 0
-        while not self.check_event(SequenceEndEvent):
-            node.value.append(self.compose_node(node, index))
-            index += 1
-        end_event = self.get_event()
-        node.end_mark = end_event.end_mark
-        return node
-
-    def compose_mapping_node(self, anchor):
-        start_event = self.get_event()
-        tag = start_event.tag
-        if tag is None or tag == '!':
-            tag = self.resolve(MappingNode, None, start_event.implicit)
-        node = MappingNode(tag, [],
-                start_event.start_mark, None,
-                flow_style=start_event.flow_style)
-        if anchor is not None:
-            self.anchors[anchor] = node
-        while not self.check_event(MappingEndEvent):
-            #key_event = self.peek_event()
-            item_key = self.compose_node(node, None)
-            #if item_key in node.value:
-            #    raise ComposerError("while composing a mapping", start_event.start_mark,
-            #            "found duplicate key", key_event.start_mark)
-            item_value = self.compose_node(node, item_key)
-            #node.value[item_key] = item_value
-            node.value.append((item_key, item_value))
-        end_event = self.get_event()
-        node.end_mark = end_event.end_mark
-        return node
-
diff --git a/lib3/yaml/constructor.py b/lib3/yaml/constructor.py
deleted file mode 100644
index 981543a..0000000
--- a/lib3/yaml/constructor.py
+++ /dev/null
@@ -1,686 +0,0 @@
-
-__all__ = ['BaseConstructor', 'SafeConstructor', 'Constructor',
-    'ConstructorError']
-
-from .error import *
-from .nodes import *
-
-import collections, datetime, base64, binascii, re, sys, types
-
-class ConstructorError(MarkedYAMLError):
-    pass
-
-class BaseConstructor:
-
-    yaml_constructors = {}
-    yaml_multi_constructors = {}
-
-    def __init__(self):
-        self.constructed_objects = {}
-        self.recursive_objects = {}
-        self.state_generators = []
-        self.deep_construct = False
-
-    def check_data(self):
-        # If there are more documents available?
-        return self.check_node()
-
-    def get_data(self):
-        # Construct and return the next document.
-        if self.check_node():
-            return self.construct_document(self.get_node())
-
-    def get_single_data(self):
-        # Ensure that the stream contains a single document and construct it.
-        node = self.get_single_node()
-        if node is not None:
-            return self.construct_document(node)
-        return None
-
-    def construct_document(self, node):
-        data = self.construct_object(node)
-        while self.state_generators:
-            state_generators = self.state_generators
-            self.state_generators = []
-            for generator in state_generators:
-                for dummy in generator:
-                    pass
-        self.constructed_objects = {}
-        self.recursive_objects = {}
-        self.deep_construct = False
-        return data
-
-    def construct_object(self, node, deep=False):
-        if node in self.constructed_objects:
-            return self.constructed_objects[node]
-        if deep:
-            old_deep = self.deep_construct
-            self.deep_construct = True
-        if node in self.recursive_objects:
-            raise ConstructorError(None, None,
-                    "found unconstructable recursive node", node.start_mark)
-        self.recursive_objects[node] = None
-        constructor = None
-        tag_suffix = None
-        if node.tag in self.yaml_constructors:
-            constructor = self.yaml_constructors[node.tag]
-        else:
-            for tag_prefix in self.yaml_multi_constructors:
-                if node.tag.startswith(tag_prefix):
-                    tag_suffix = node.tag[len(tag_prefix):]
-                    constructor = self.yaml_multi_constructors[tag_prefix]
-                    break
-            else:
-                if None in self.yaml_multi_constructors:
-                    tag_suffix = node.tag
-                    constructor = self.yaml_multi_constructors[None]
-                elif None in self.yaml_constructors:
-                    constructor = self.yaml_constructors[None]
-                elif isinstance(node, ScalarNode):
-                    constructor = self.__class__.construct_scalar
-                elif isinstance(node, SequenceNode):
-                    constructor = self.__class__.construct_sequence
-                elif isinstance(node, MappingNode):
-                    constructor = self.__class__.construct_mapping
-        if tag_suffix is None:
-            data = constructor(self, node)
-        else:
-            data = constructor(self, tag_suffix, node)
-        if isinstance(data, types.GeneratorType):
-            generator = data
-            data = next(generator)
-            if self.deep_construct:
-                for dummy in generator:
-                    pass
-            else:
-                self.state_generators.append(generator)
-        self.constructed_objects[node] = data
-        del self.recursive_objects[node]
-        if deep:
-            self.deep_construct = old_deep
-        return data
-
-    def construct_scalar(self, node):
-        if not isinstance(node, ScalarNode):
-            raise ConstructorError(None, None,
-                    "expected a scalar node, but found %s" % node.id,
-                    node.start_mark)
-        return node.value
-
-    def construct_sequence(self, node, deep=False):
-        if not isinstance(node, SequenceNode):
-            raise ConstructorError(None, None,
-                    "expected a sequence node, but found %s" % node.id,
-                    node.start_mark)
-        return [self.construct_object(child, deep=deep)
-                for child in node.value]
-
-    def construct_mapping(self, node, deep=False):
-        if not isinstance(node, MappingNode):
-            raise ConstructorError(None, None,
-                    "expected a mapping node, but found %s" % node.id,
-                    node.start_mark)
-        mapping = {}
-        for key_node, value_node in node.value:
-            key = self.construct_object(key_node, deep=deep)
-            if not isinstance(key, collections.Hashable):
-                raise ConstructorError("while constructing a mapping", node.start_mark,
-                        "found unhashable key", key_node.start_mark)
-            value = self.construct_object(value_node, deep=deep)
-            mapping[key] = value
-        return mapping
-
-    def construct_pairs(self, node, deep=False):
-        if not isinstance(node, MappingNode):
-            raise ConstructorError(None, None,
-                    "expected a mapping node, but found %s" % node.id,
-                    node.start_mark)
-        pairs = []
-        for key_node, value_node in node.value:
-            key = self.construct_object(key_node, deep=deep)
-            value = self.construct_object(value_node, deep=deep)
-            pairs.append((key, value))
-        return pairs
-
-    @classmethod
-    def add_constructor(cls, tag, constructor):
-        if not 'yaml_constructors' in cls.__dict__:
-            cls.yaml_constructors = cls.yaml_constructors.copy()
-        cls.yaml_constructors[tag] = constructor
-
-    @classmethod
-    def add_multi_constructor(cls, tag_prefix, multi_constructor):
-        if not 'yaml_multi_constructors' in cls.__dict__:
-            cls.yaml_multi_constructors = cls.yaml_multi_constructors.copy()
-        cls.yaml_multi_constructors[tag_prefix] = multi_constructor
-
-class SafeConstructor(BaseConstructor):
-
-    def construct_scalar(self, node):
-        if isinstance(node, MappingNode):
-            for key_node, value_node in node.value:
-                if key_node.tag == 'tag:yaml.org,2002:value':
-                    return self.construct_scalar(value_node)
-        return super().construct_scalar(node)
-
-    def flatten_mapping(self, node):
-        merge = []
-        index = 0
-        while index < len(node.value):
-            key_node, value_node = node.value[index]
-            if key_node.tag == 'tag:yaml.org,2002:merge':
-                del node.value[index]
-                if isinstance(value_node, MappingNode):
-                    self.flatten_mapping(value_node)
-                    merge.extend(value_node.value)
-                elif isinstance(value_node, SequenceNode):
-                    submerge = []
-                    for subnode in value_node.value:
-                        if not isinstance(subnode, MappingNode):
-                            raise ConstructorError("while constructing a mapping",
-                                    node.start_mark,
-                                    "expected a mapping for merging, but found %s"
-                                    % subnode.id, subnode.start_mark)
-                        self.flatten_mapping(subnode)
-                        submerge.append(subnode.value)
-                    submerge.reverse()
-                    for value in submerge:
-                        merge.extend(value)
-                else:
-                    raise ConstructorError("while constructing a mapping", node.start_mark,
-                            "expected a mapping or list of mappings for merging, but found %s"
-                            % value_node.id, value_node.start_mark)
-            elif key_node.tag == 'tag:yaml.org,2002:value':
-                key_node.tag = 'tag:yaml.org,2002:str'
-                index += 1
-            else:
-                index += 1
-        if merge:
-            node.value = merge + node.value
-
-    def construct_mapping(self, node, deep=False):
-        if isinstance(node, MappingNode):
-            self.flatten_mapping(node)
-        return super().construct_mapping(node, deep=deep)
-
-    def construct_yaml_null(self, node):
-        self.construct_scalar(node)
-        return None
-
-    bool_values = {
-        'yes':      True,
-        'no':       False,
-        'true':     True,
-        'false':    False,
-        'on':       True,
-        'off':      False,
-    }
-
-    def construct_yaml_bool(self, node):
-        value = self.construct_scalar(node)
-        return self.bool_values[value.lower()]
-
-    def construct_yaml_int(self, node):
-        value = self.construct_scalar(node)
-        value = value.replace('_', '')
-        sign = +1
-        if value[0] == '-':
-            sign = -1
-        if value[0] in '+-':
-            value = value[1:]
-        if value == '0':
-            return 0
-        elif value.startswith('0b'):
-            return sign*int(value[2:], 2)
-        elif value.startswith('0x'):
-            return sign*int(value[2:], 16)
-        elif value[0] == '0':
-            return sign*int(value, 8)
-        elif ':' in value:
-            digits = [int(part) for part in value.split(':')]
-            digits.reverse()
-            base = 1
-            value = 0
-            for digit in digits:
-                value += digit*base
-                base *= 60
-            return sign*value
-        else:
-            return sign*int(value)
-
-    inf_value = 1e300
-    while inf_value != inf_value*inf_value:
-        inf_value *= inf_value
-    nan_value = -inf_value/inf_value   # Trying to make a quiet NaN (like C99).
-
-    def construct_yaml_float(self, node):
-        value = self.construct_scalar(node)
-        value = value.replace('_', '').lower()
-        sign = +1
-        if value[0] == '-':
-            sign = -1
-        if value[0] in '+-':
-            value = value[1:]
-        if value == '.inf':
-            return sign*self.inf_value
-        elif value == '.nan':
-            return self.nan_value
-        elif ':' in value:
-            digits = [float(part) for part in value.split(':')]
-            digits.reverse()
-            base = 1
-            value = 0.0
-            for digit in digits:
-                value += digit*base
-                base *= 60
-            return sign*value
-        else:
-            return sign*float(value)
-
-    def construct_yaml_binary(self, node):
-        try:
-            value = self.construct_scalar(node).encode('ascii')
-        except UnicodeEncodeError as exc:
-            raise ConstructorError(None, None,
-                    "failed to convert base64 data into ascii: %s" % exc,
-                    node.start_mark)
-        try:
-            if hasattr(base64, 'decodebytes'):
-                return base64.decodebytes(value)
-            else:
-                return base64.decodestring(value)
-        except binascii.Error as exc:
-            raise ConstructorError(None, None,
-                    "failed to decode base64 data: %s" % exc, node.start_mark)
-
-    timestamp_regexp = re.compile(
-            r'''^(?P<year>[0-9][0-9][0-9][0-9])
-                -(?P<month>[0-9][0-9]?)
-                -(?P<day>[0-9][0-9]?)
-                (?:(?:[Tt]|[ \t]+)
-                (?P<hour>[0-9][0-9]?)
-                :(?P<minute>[0-9][0-9])
-                :(?P<second>[0-9][0-9])
-                (?:\.(?P<fraction>[0-9]*))?
-                (?:[ \t]*(?P<tz>Z|(?P<tz_sign>[-+])(?P<tz_hour>[0-9][0-9]?)
-                (?::(?P<tz_minute>[0-9][0-9]))?))?)?$''', re.X)
-
-    def construct_yaml_timestamp(self, node):
-        value = self.construct_scalar(node)
-        match = self.timestamp_regexp.match(node.value)
-        values = match.groupdict()
-        year = int(values['year'])
-        month = int(values['month'])
-        day = int(values['day'])
-        if not values['hour']:
-            return datetime.date(year, month, day)
-        hour = int(values['hour'])
-        minute = int(values['minute'])
-        second = int(values['second'])
-        fraction = 0
-        if values['fraction']:
-            fraction = values['fraction'][:6]
-            while len(fraction) < 6:
-                fraction += '0'
-            fraction = int(fraction)
-        delta = None
-        if values['tz_sign']:
-            tz_hour = int(values['tz_hour'])
-            tz_minute = int(values['tz_minute'] or 0)
-            delta = datetime.timedelta(hours=tz_hour, minutes=tz_minute)
-            if values['tz_sign'] == '-':
-                delta = -delta
-        data = datetime.datetime(year, month, day, hour, minute, second, fraction)
-        if delta:
-            data -= delta
-        return data
-
-    def construct_yaml_omap(self, node):
-        # Note: we do not check for duplicate keys, because it's too
-        # CPU-expensive.
-        omap = []
-        yield omap
-        if not isinstance(node, SequenceNode):
-            raise ConstructorError("while constructing an ordered map", node.start_mark,
-                    "expected a sequence, but found %s" % node.id, node.start_mark)
-        for subnode in node.value:
-            if not isinstance(subnode, MappingNode):
-                raise ConstructorError("while constructing an ordered map", node.start_mark,
-                        "expected a mapping of length 1, but found %s" % subnode.id,
-                        subnode.start_mark)
-            if len(subnode.value) != 1:
-                raise ConstructorError("while constructing an ordered map", node.start_mark,
-                        "expected a single mapping item, but found %d items" % len(subnode.value),
-                        subnode.start_mark)
-            key_node, value_node = subnode.value[0]
-            key = self.construct_object(key_node)
-            value = self.construct_object(value_node)
-            omap.append((key, value))
-
-    def construct_yaml_pairs(self, node):
-        # Note: the same code as `construct_yaml_omap`.
-        pairs = []
-        yield pairs
-        if not isinstance(node, SequenceNode):
-            raise ConstructorError("while constructing pairs", node.start_mark,
-                    "expected a sequence, but found %s" % node.id, node.start_mark)
-        for subnode in node.value:
-            if not isinstance(subnode, MappingNode):
-                raise ConstructorError("while constructing pairs", node.start_mark,
-                        "expected a mapping of length 1, but found %s" % subnode.id,
-                        subnode.start_mark)
-            if len(subnode.value) != 1:
-                raise ConstructorError("while constructing pairs", node.start_mark,
-                        "expected a single mapping item, but found %d items" % len(subnode.value),
-                        subnode.start_mark)
-            key_node, value_node = subnode.value[0]
-            key = self.construct_object(key_node)
-            value = self.construct_object(value_node)
-            pairs.append((key, value))
-
-    def construct_yaml_set(self, node):
-        data = set()
-        yield data
-        value = self.construct_mapping(node)
-        data.update(value)
-
-    def construct_yaml_str(self, node):
-        return self.construct_scalar(node)
-
-    def construct_yaml_seq(self, node):
-        data = []
-        yield data
-        data.extend(self.construct_sequence(node))
-
-    def construct_yaml_map(self, node):
-        data = {}
-        yield data
-        value = self.construct_mapping(node)
-        data.update(value)
-
-    def construct_yaml_object(self, node, cls):
-        data = cls.__new__(cls)
-        yield data
-        if hasattr(data, '__setstate__'):
-            state = self.construct_mapping(node, deep=True)
-            data.__setstate__(state)
-        else:
-            state = self.construct_mapping(node)
-            data.__dict__.update(state)
-
-    def construct_undefined(self, node):
-        raise ConstructorError(None, None,
-                "could not determine a constructor for the tag %r" % node.tag,
-                node.start_mark)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:null',
-        SafeConstructor.construct_yaml_null)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:bool',
-        SafeConstructor.construct_yaml_bool)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:int',
-        SafeConstructor.construct_yaml_int)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:float',
-        SafeConstructor.construct_yaml_float)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:binary',
-        SafeConstructor.construct_yaml_binary)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:timestamp',
-        SafeConstructor.construct_yaml_timestamp)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:omap',
-        SafeConstructor.construct_yaml_omap)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:pairs',
-        SafeConstructor.construct_yaml_pairs)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:set',
-        SafeConstructor.construct_yaml_set)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:str',
-        SafeConstructor.construct_yaml_str)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:seq',
-        SafeConstructor.construct_yaml_seq)
-
-SafeConstructor.add_constructor(
-        'tag:yaml.org,2002:map',
-        SafeConstructor.construct_yaml_map)
-
-SafeConstructor.add_constructor(None,
-        SafeConstructor.construct_undefined)
-
-class Constructor(SafeConstructor):
-
-    def construct_python_str(self, node):
-        return self.construct_scalar(node)
-
-    def construct_python_unicode(self, node):
-        return self.construct_scalar(node)
-
-    def construct_python_bytes(self, node):
-        try:
-            value = self.construct_scalar(node).encode('ascii')
-        except UnicodeEncodeError as exc:
-            raise ConstructorError(None, None,
-                    "failed to convert base64 data into ascii: %s" % exc,
-                    node.start_mark)
-        try:
-            if hasattr(base64, 'decodebytes'):
-                return base64.decodebytes(value)
-            else:
-                return base64.decodestring(value)
-        except binascii.Error as exc:
-            raise ConstructorError(None, None,
-                    "failed to decode base64 data: %s" % exc, node.start_mark)
-
-    def construct_python_long(self, node):
-        return self.construct_yaml_int(node)
-
-    def construct_python_complex(self, node):
-       return complex(self.construct_scalar(node))
-
-    def construct_python_tuple(self, node):
-        return tuple(self.construct_sequence(node))
-
-    def find_python_module(self, name, mark):
-        if not name:
-            raise ConstructorError("while constructing a Python module", mark,
-                    "expected non-empty name appended to the tag", mark)
-        try:
-            __import__(name)
-        except ImportError as exc:
-            raise ConstructorError("while constructing a Python module", mark,
-                    "cannot find module %r (%s)" % (name, exc), mark)
-        return sys.modules[name]
-
-    def find_python_name(self, name, mark):
-        if not name:
-            raise ConstructorError("while constructing a Python object", mark,
-                    "expected non-empty name appended to the tag", mark)
-        if '.' in name:
-            module_name, object_name = name.rsplit('.', 1)
-        else:
-            module_name = 'builtins'
-            object_name = name
-        try:
-            __import__(module_name)
-        except ImportError as exc:
-            raise ConstructorError("while constructing a Python object", mark,
-                    "cannot find module %r (%s)" % (module_name, exc), mark)
-        module = sys.modules[module_name]
-        if not hasattr(module, object_name):
-            raise ConstructorError("while constructing a Python object", mark,
-                    "cannot find %r in the module %r"
-                    % (object_name, module.__name__), mark)
-        return getattr(module, object_name)
-
-    def construct_python_name(self, suffix, node):
-        value = self.construct_scalar(node)
-        if value:
-            raise ConstructorError("while constructing a Python name", node.start_mark,
-                    "expected the empty value, but found %r" % value, node.start_mark)
-        return self.find_python_name(suffix, node.start_mark)
-
-    def construct_python_module(self, suffix, node):
-        value = self.construct_scalar(node)
-        if value:
-            raise ConstructorError("while constructing a Python module", node.start_mark,
-                    "expected the empty value, but found %r" % value, node.start_mark)
-        return self.find_python_module(suffix, node.start_mark)
-
-    def make_python_instance(self, suffix, node,
-            args=None, kwds=None, newobj=False):
-        if not args:
-            args = []
-        if not kwds:
-            kwds = {}
-        cls = self.find_python_name(suffix, node.start_mark)
-        if newobj and isinstance(cls, type):
-            return cls.__new__(cls, *args, **kwds)
-        else:
-            return cls(*args, **kwds)
-
-    def set_python_instance_state(self, instance, state):
-        if hasattr(instance, '__setstate__'):
-            instance.__setstate__(state)
-        else:
-            slotstate = {}
-            if isinstance(state, tuple) and len(state) == 2:
-                state, slotstate = state
-            if hasattr(instance, '__dict__'):
-                instance.__dict__.update(state)
-            elif state:
-                slotstate.update(state)
-            for key, value in slotstate.items():
-                setattr(object, key, value)
-
-    def construct_python_object(self, suffix, node):
-        # Format:
-        #   !!python/object:module.name { ... state ... }
-        instance = self.make_python_instance(suffix, node, newobj=True)
-        yield instance
-        deep = hasattr(instance, '__setstate__')
-        state = self.construct_mapping(node, deep=deep)
-        self.set_python_instance_state(instance, state)
-
-    def construct_python_object_apply(self, suffix, node, newobj=False):
-        # Format:
-        #   !!python/object/apply       # (or !!python/object/new)
-        #   args: [ ... arguments ... ]
-        #   kwds: { ... keywords ... }
-        #   state: ... state ...
-        #   listitems: [ ... listitems ... ]
-        #   dictitems: { ... dictitems ... }
-        # or short format:
-        #   !!python/object/apply [ ... arguments ... ]
-        # The difference between !!python/object/apply and !!python/object/new
-        # is how an object is created, check make_python_instance for details.
-        if isinstance(node, SequenceNode):
-            args = self.construct_sequence(node, deep=True)
-            kwds = {}
-            state = {}
-            listitems = []
-            dictitems = {}
-        else:
-            value = self.construct_mapping(node, deep=True)
-            args = value.get('args', [])
-            kwds = value.get('kwds', {})
-            state = value.get('state', {})
-            listitems = value.get('listitems', [])
-            dictitems = value.get('dictitems', {})
-        instance = self.make_python_instance(suffix, node, args, kwds, newobj)
-        if state:
-            self.set_python_instance_state(instance, state)
-        if listitems:
-            instance.extend(listitems)
-        if dictitems:
-            for key in dictitems:
-                instance[key] = dictitems[key]
-        return instance
-
-    def construct_python_object_new(self, suffix, node):
-        return self.construct_python_object_apply(suffix, node, newobj=True)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/none',
-    Constructor.construct_yaml_null)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/bool',
-    Constructor.construct_yaml_bool)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/str',
-    Constructor.construct_python_str)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/unicode',
-    Constructor.construct_python_unicode)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/bytes',
-    Constructor.construct_python_bytes)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/int',
-    Constructor.construct_yaml_int)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/long',
-    Constructor.construct_python_long)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/float',
-    Constructor.construct_yaml_float)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/complex',
-    Constructor.construct_python_complex)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/list',
-    Constructor.construct_yaml_seq)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/tuple',
-    Constructor.construct_python_tuple)
-
-Constructor.add_constructor(
-    'tag:yaml.org,2002:python/dict',
-    Constructor.construct_yaml_map)
-
-Constructor.add_multi_constructor(
-    'tag:yaml.org,2002:python/name:',
-    Constructor.construct_python_name)
-
-Constructor.add_multi_constructor(
-    'tag:yaml.org,2002:python/module:',
-    Constructor.construct_python_module)
-
-Constructor.add_multi_constructor(
-    'tag:yaml.org,2002:python/object:',
-    Constructor.construct_python_object)
-
-Constructor.add_multi_constructor(
-    'tag:yaml.org,2002:python/object/apply:',
-    Constructor.construct_python_object_apply)
-
-Constructor.add_multi_constructor(
-    'tag:yaml.org,2002:python/object/new:',
-    Constructor.construct_python_object_new)
-
diff --git a/lib3/yaml/cyaml.py b/lib3/yaml/cyaml.py
deleted file mode 100644
index ac8b0b7..0000000
--- a/lib3/yaml/cyaml.py
+++ /dev/null
@@ -1,86 +0,0 @@
-
-__all__ = ['CBaseLoader', 'CSafeLoader', 'CLoader', 'CDangerLoader',
-        'CBaseDumper', 'CSafeDumper', 'CDumper', 'CDangerDumper']
-
-from _yaml import CParser, CEmitter
-
-from .constructor import *
-
-from .serializer import *
-from .representer import *
-
-from .resolver import *
-
-class CBaseLoader(CParser, BaseConstructor, BaseResolver):
-
-    def __init__(self, stream):
-        CParser.__init__(self, stream)
-        BaseConstructor.__init__(self)
-        BaseResolver.__init__(self)
-
-class CLoader(CParser, SafeConstructor, Resolver):
-
-    def __init__(self, stream):
-        CParser.__init__(self, stream)
-        SafeConstructor.__init__(self)
-        Resolver.__init__(self)
-CSafeLoader = CLoader
-
-class CDangerLoader(CParser, Constructor, Resolver):
-
-    def __init__(self, stream):
-        CParser.__init__(self, stream)
-        Constructor.__init__(self)
-        Resolver.__init__(self)
-
-class CBaseDumper(CEmitter, BaseRepresenter, BaseResolver):
-
-    def __init__(self, stream,
-            default_style=None, default_flow_style=None,
-            canonical=None, indent=None, width=None,
-            allow_unicode=None, line_break=None,
-            encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
-        CEmitter.__init__(self, stream, canonical=canonical,
-                indent=indent, width=width, encoding=encoding,
-                allow_unicode=allow_unicode, line_break=line_break,
-                explicit_start=explicit_start, explicit_end=explicit_end,
-                version=version, tags=tags)
-        Representer.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
-        Resolver.__init__(self)
-
-class CDumper(CEmitter, SafeRepresenter, Resolver):
-
-    def __init__(self, stream,
-            default_style=None, default_flow_style=None,
-            canonical=None, indent=None, width=None,
-            allow_unicode=None, line_break=None,
-            encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
-        CEmitter.__init__(self, stream, canonical=canonical,
-                indent=indent, width=width, encoding=encoding,
-                allow_unicode=allow_unicode, line_break=line_break,
-                explicit_start=explicit_start, explicit_end=explicit_end,
-                version=version, tags=tags)
-        SafeRepresenter.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
-        Resolver.__init__(self)
-CSafeDumper = CDumper
-
-class CDangerDumper(CEmitter, Serializer, Representer, Resolver):
-
-    def __init__(self, stream,
-            default_style=None, default_flow_style=None,
-            canonical=None, indent=None, width=None,
-            allow_unicode=None, line_break=None,
-            encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
-        CEmitter.__init__(self, stream, canonical=canonical,
-                indent=indent, width=width, encoding=encoding,
-                allow_unicode=allow_unicode, line_break=line_break,
-                explicit_start=explicit_start, explicit_end=explicit_end,
-                version=version, tags=tags)
-        Representer.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
-        Resolver.__init__(self)
diff --git a/lib3/yaml/dumper.py b/lib3/yaml/dumper.py
deleted file mode 100644
index b2d3a07..0000000
--- a/lib3/yaml/dumper.py
+++ /dev/null
@@ -1,62 +0,0 @@
-
-__all__ = ['BaseDumper', 'SafeDumper', 'Dumper', 'DangerDumper']
-
-from .emitter import *
-from .serializer import *
-from .representer import *
-from .resolver import *
-
-class BaseDumper(Emitter, Serializer, BaseRepresenter, BaseResolver):
-
-    def __init__(self, stream,
-            default_style=None, default_flow_style=None,
-            canonical=None, indent=None, width=None,
-            allow_unicode=None, line_break=None,
-            encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
-        Emitter.__init__(self, stream, canonical=canonical,
-                indent=indent, width=width,
-                allow_unicode=allow_unicode, line_break=line_break)
-        Serializer.__init__(self, encoding=encoding,
-                explicit_start=explicit_start, explicit_end=explicit_end,
-                version=version, tags=tags)
-        Representer.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
-        Resolver.__init__(self)
-
-class Dumper(Emitter, Serializer, SafeRepresenter, Resolver):
-
-    def __init__(self, stream,
-            default_style=None, default_flow_style=None,
-            canonical=None, indent=None, width=None,
-            allow_unicode=None, line_break=None,
-            encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
-        Emitter.__init__(self, stream, canonical=canonical,
-                indent=indent, width=width,
-                allow_unicode=allow_unicode, line_break=line_break)
-        Serializer.__init__(self, encoding=encoding,
-                explicit_start=explicit_start, explicit_end=explicit_end,
-                version=version, tags=tags)
-        SafeRepresenter.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
-        Resolver.__init__(self)
-SafeDumper = Dumper
-
-class DangerDumper(Emitter, Serializer, Representer, Resolver):
-
-    def __init__(self, stream,
-            default_style=None, default_flow_style=None,
-            canonical=None, indent=None, width=None,
-            allow_unicode=None, line_break=None,
-            encoding=None, explicit_start=None, explicit_end=None,
-            version=None, tags=None):
-        Emitter.__init__(self, stream, canonical=canonical,
-                indent=indent, width=width,
-                allow_unicode=allow_unicode, line_break=line_break)
-        Serializer.__init__(self, encoding=encoding,
-                explicit_start=explicit_start, explicit_end=explicit_end,
-                version=version, tags=tags)
-        Representer.__init__(self, default_style=default_style,
-                default_flow_style=default_flow_style)
-        Resolver.__init__(self)
diff --git a/lib3/yaml/emitter.py b/lib3/yaml/emitter.py
deleted file mode 100644
index 5704bc8..0000000
--- a/lib3/yaml/emitter.py
+++ /dev/null
@@ -1,1137 +0,0 @@
-
-# Emitter expects events obeying the following grammar:
-# stream ::= STREAM-START document* STREAM-END
-# document ::= DOCUMENT-START node DOCUMENT-END
-# node ::= SCALAR | sequence | mapping
-# sequence ::= SEQUENCE-START node* SEQUENCE-END
-# mapping ::= MAPPING-START (node node)* MAPPING-END
-
-__all__ = ['Emitter', 'EmitterError']
-
-from .error import YAMLError
-from .events import *
-
-class EmitterError(YAMLError):
-    pass
-
-class ScalarAnalysis:
-    def __init__(self, scalar, empty, multiline,
-            allow_flow_plain, allow_block_plain,
-            allow_single_quoted, allow_double_quoted,
-            allow_block):
-        self.scalar = scalar
-        self.empty = empty
-        self.multiline = multiline
-        self.allow_flow_plain = allow_flow_plain
-        self.allow_block_plain = allow_block_plain
-        self.allow_single_quoted = allow_single_quoted
-        self.allow_double_quoted = allow_double_quoted
-        self.allow_block = allow_block
-
-class Emitter:
-
-    DEFAULT_TAG_PREFIXES = {
-        '!' : '!',
-        'tag:yaml.org,2002:' : '!!',
-    }
-
-    def __init__(self, stream, canonical=None, indent=None, width=None,
-            allow_unicode=None, line_break=None):
-
-        # The stream should have the methods `write` and possibly `flush`.
-        self.stream = stream
-
-        # Encoding can be overridden by STREAM-START.
-        self.encoding = None
-
-        # Emitter is a state machine with a stack of states to handle nested
-        # structures.
-        self.states = []
-        self.state = self.expect_stream_start
-
-        # Current event and the event queue.
-        self.events = []
-        self.event = None
-
-        # The current indentation level and the stack of previous indents.
-        self.indents = []
-        self.indent = None
-
-        # Flow level.
-        self.flow_level = 0
-
-        # Contexts.
-        self.root_context = False
-        self.sequence_context = False
-        self.mapping_context = False
-        self.simple_key_context = False
-
-        # Characteristics of the last emitted character:
-        #  - current position.
-        #  - is it a whitespace?
-        #  - is it an indention character
-        #    (indentation space, '-', '?', or ':')?
-        self.line = 0
-        self.column = 0
-        self.whitespace = True
-        self.indention = True
-
-        # Whether the document requires an explicit document indicator
-        self.open_ended = False
-
-        # Formatting details.
-        self.canonical = canonical
-        self.allow_unicode = allow_unicode
-        self.best_indent = 2
-        if indent and 1 < indent < 10:
-            self.best_indent = indent
-        self.best_width = 80
-        if width and width > self.best_indent*2:
-            self.best_width = width
-        self.best_line_break = '\n'
-        if line_break in ['\r', '\n', '\r\n']:
-            self.best_line_break = line_break
-
-        # Tag prefixes.
-        self.tag_prefixes = None
-
-        # Prepared anchor and tag.
-        self.prepared_anchor = None
-        self.prepared_tag = None
-
-        # Scalar analysis and style.
-        self.analysis = None
-        self.style = None
-
-    def dispose(self):
-        # Reset the state attributes (to clear self-references)
-        self.states = []
-        self.state = None
-
-    def emit(self, event):
-        self.events.append(event)
-        while not self.need_more_events():
-            self.event = self.events.pop(0)
-            self.state()
-            self.event = None
-
-    # In some cases, we wait for a few next events before emitting.
-
-    def need_more_events(self):
-        if not self.events:
-            return True
-        event = self.events[0]
-        if isinstance(event, DocumentStartEvent):
-            return self.need_events(1)
-        elif isinstance(event, SequenceStartEvent):
-            return self.need_events(2)
-        elif isinstance(event, MappingStartEvent):
-            return self.need_events(3)
-        else:
-            return False
-
-    def need_events(self, count):
-        level = 0
-        for event in self.events[1:]:
-            if isinstance(event, (DocumentStartEvent, CollectionStartEvent)):
-                level += 1
-            elif isinstance(event, (DocumentEndEvent, CollectionEndEvent)):
-                level -= 1
-            elif isinstance(event, StreamEndEvent):
-                level = -1
-            if level < 0:
-                return False
-        return (len(self.events) < count+1)
-
-    def increase_indent(self, flow=False, indentless=False):
-        self.indents.append(self.indent)
-        if self.indent is None:
-            if flow:
-                self.indent = self.best_indent
-            else:
-                self.indent = 0
-        elif not indentless:
-            self.indent += self.best_indent
-
-    # States.
-
-    # Stream handlers.
-
-    def expect_stream_start(self):
-        if isinstance(self.event, StreamStartEvent):
-            if self.event.encoding and not hasattr(self.stream, 'encoding'):
-                self.encoding = self.event.encoding
-            self.write_stream_start()
-            self.state = self.expect_first_document_start
-        else:
-            raise EmitterError("expected StreamStartEvent, but got %s"
-                    % self.event)
-
-    def expect_nothing(self):
-        raise EmitterError("expected nothing, but got %s" % self.event)
-
-    # Document handlers.
-
-    def expect_first_document_start(self):
-        return self.expect_document_start(first=True)
-
-    def expect_document_start(self, first=False):
-        if isinstance(self.event, DocumentStartEvent):
-            if (self.event.version or self.event.tags) and self.open_ended:
-                self.write_indicator('...', True)
-                self.write_indent()
-            if self.event.version:
-                version_text = self.prepare_version(self.event.version)
-                self.write_version_directive(version_text)
-            self.tag_prefixes = self.DEFAULT_TAG_PREFIXES.copy()
-            if self.event.tags:
-                handles = sorted(self.event.tags.keys())
-                for handle in handles:
-                    prefix = self.event.tags[handle]
-                    self.tag_prefixes[prefix] = handle
-                    handle_text = self.prepare_tag_handle(handle)
-                    prefix_text = self.prepare_tag_prefix(prefix)
-                    self.write_tag_directive(handle_text, prefix_text)
-            implicit = (first and not self.event.explicit and not self.canonical
-                    and not self.event.version and not self.event.tags
-                    and not self.check_empty_document())
-            if not implicit:
-                self.write_indent()
-                self.write_indicator('---', True)
-                if self.canonical:
-                    self.write_indent()
-            self.state = self.expect_document_root
-        elif isinstance(self.event, StreamEndEvent):
-            if self.open_ended:
-                self.write_indicator('...', True)
-                self.write_indent()
-            self.write_stream_end()
-            self.state = self.expect_nothing
-        else:
-            raise EmitterError("expected DocumentStartEvent, but got %s"
-                    % self.event)
-
-    def expect_document_end(self):
-        if isinstance(self.event, DocumentEndEvent):
-            self.write_indent()
-            if self.event.explicit:
-                self.write_indicator('...', True)
-                self.write_indent()
-            self.flush_stream()
-            self.state = self.expect_document_start
-        else:
-            raise EmitterError("expected DocumentEndEvent, but got %s"
-                    % self.event)
-
-    def expect_document_root(self):
-        self.states.append(self.expect_document_end)
-        self.expect_node(root=True)
-
-    # Node handlers.
-
-    def expect_node(self, root=False, sequence=False, mapping=False,
-            simple_key=False):
-        self.root_context = root
-        self.sequence_context = sequence
-        self.mapping_context = mapping
-        self.simple_key_context = simple_key
-        if isinstance(self.event, AliasEvent):
-            self.expect_alias()
-        elif isinstance(self.event, (ScalarEvent, CollectionStartEvent)):
-            self.process_anchor('&')
-            self.process_tag()
-            if isinstance(self.event, ScalarEvent):
-                self.expect_scalar()
-            elif isinstance(self.event, SequenceStartEvent):
-                if self.flow_level or self.canonical or self.event.flow_style   \
-                        or self.check_empty_sequence():
-                    self.expect_flow_sequence()
-                else:
-                    self.expect_block_sequence()
-            elif isinstance(self.event, MappingStartEvent):
-                if self.flow_level or self.canonical or self.event.flow_style   \
-                        or self.check_empty_mapping():
-                    self.expect_flow_mapping()
-                else:
-                    self.expect_block_mapping()
-        else:
-            raise EmitterError("expected NodeEvent, but got %s" % self.event)
-
-    def expect_alias(self):
-        if self.event.anchor is None:
-            raise EmitterError("anchor is not specified for alias")
-        self.process_anchor('*')
-        self.state = self.states.pop()
-
-    def expect_scalar(self):
-        self.increase_indent(flow=True)
-        self.process_scalar()
-        self.indent = self.indents.pop()
-        self.state = self.states.pop()
-
-    # Flow sequence handlers.
-
-    def expect_flow_sequence(self):
-        self.write_indicator('[', True, whitespace=True)
-        self.flow_level += 1
-        self.increase_indent(flow=True)
-        self.state = self.expect_first_flow_sequence_item
-
-    def expect_first_flow_sequence_item(self):
-        if isinstance(self.event, SequenceEndEvent):
-            self.indent = self.indents.pop()
-            self.flow_level -= 1
-            self.write_indicator(']', False)
-            self.state = self.states.pop()
-        else:
-            if self.canonical or self.column > self.best_width:
-                self.write_indent()
-            self.states.append(self.expect_flow_sequence_item)
-            self.expect_node(sequence=True)
-
-    def expect_flow_sequence_item(self):
-        if isinstance(self.event, SequenceEndEvent):
-            self.indent = self.indents.pop()
-            self.flow_level -= 1
-            if self.canonical:
-                self.write_indicator(',', False)
-                self.write_indent()
-            self.write_indicator(']', False)
-            self.state = self.states.pop()
-        else:
-            self.write_indicator(',', False)
-            if self.canonical or self.column > self.best_width:
-                self.write_indent()
-            self.states.append(self.expect_flow_sequence_item)
-            self.expect_node(sequence=True)
-
-    # Flow mapping handlers.
-
-    def expect_flow_mapping(self):
-        self.write_indicator('{', True, whitespace=True)
-        self.flow_level += 1
-        self.increase_indent(flow=True)
-        self.state = self.expect_first_flow_mapping_key
-
-    def expect_first_flow_mapping_key(self):
-        if isinstance(self.event, MappingEndEvent):
-            self.indent = self.indents.pop()
-            self.flow_level -= 1
-            self.write_indicator('}', False)
-            self.state = self.states.pop()
-        else:
-            if self.canonical or self.column > self.best_width:
-                self.write_indent()
-            if not self.canonical and self.check_simple_key():
-                self.states.append(self.expect_flow_mapping_simple_value)
-                self.expect_node(mapping=True, simple_key=True)
-            else:
-                self.write_indicator('?', True)
-                self.states.append(self.expect_flow_mapping_value)
-                self.expect_node(mapping=True)
-
-    def expect_flow_mapping_key(self):
-        if isinstance(self.event, MappingEndEvent):
-            self.indent = self.indents.pop()
-            self.flow_level -= 1
-            if self.canonical:
-                self.write_indicator(',', False)
-                self.write_indent()
-            self.write_indicator('}', False)
-            self.state = self.states.pop()
-        else:
-            self.write_indicator(',', False)
-            if self.canonical or self.column > self.best_width:
-                self.write_indent()
-            if not self.canonical and self.check_simple_key():
-                self.states.append(self.expect_flow_mapping_simple_value)
-                self.expect_node(mapping=True, simple_key=True)
-            else:
-                self.write_indicator('?', True)
-                self.states.append(self.expect_flow_mapping_value)
-                self.expect_node(mapping=True)
-
-    def expect_flow_mapping_simple_value(self):
-        self.write_indicator(':', False)
-        self.states.append(self.expect_flow_mapping_key)
-        self.expect_node(mapping=True)
-
-    def expect_flow_mapping_value(self):
-        if self.canonical or self.column > self.best_width:
-            self.write_indent()
-        self.write_indicator(':', True)
-        self.states.append(self.expect_flow_mapping_key)
-        self.expect_node(mapping=True)
-
-    # Block sequence handlers.
-
-    def expect_block_sequence(self):
-        indentless = (self.mapping_context and not self.indention)
-        self.increase_indent(flow=False, indentless=indentless)
-        self.state = self.expect_first_block_sequence_item
-
-    def expect_first_block_sequence_item(self):
-        return self.expect_block_sequence_item(first=True)
-
-    def expect_block_sequence_item(self, first=False):
-        if not first and isinstance(self.event, SequenceEndEvent):
-            self.indent = self.indents.pop()
-            self.state = self.states.pop()
-        else:
-            self.write_indent()
-            self.write_indicator('-', True, indention=True)
-            self.states.append(self.expect_block_sequence_item)
-            self.expect_node(sequence=True)
-
-    # Block mapping handlers.
-
-    def expect_block_mapping(self):
-        self.increase_indent(flow=False)
-        self.state = self.expect_first_block_mapping_key
-
-    def expect_first_block_mapping_key(self):
-        return self.expect_block_mapping_key(first=True)
-
-    def expect_block_mapping_key(self, first=False):
-        if not first and isinstance(self.event, MappingEndEvent):
-            self.indent = self.indents.pop()
-            self.state = self.states.pop()
-        else:
-            self.write_indent()
-            if self.check_simple_key():
-                self.states.append(self.expect_block_mapping_simple_value)
-                self.expect_node(mapping=True, simple_key=True)
-            else:
-                self.write_indicator('?', True, indention=True)
-                self.states.append(self.expect_block_mapping_value)
-                self.expect_node(mapping=True)
-
-    def expect_block_mapping_simple_value(self):
-        self.write_indicator(':', False)
-        self.states.append(self.expect_block_mapping_key)
-        self.expect_node(mapping=True)
-
-    def expect_block_mapping_value(self):
-        self.write_indent()
-        self.write_indicator(':', True, indention=True)
-        self.states.append(self.expect_block_mapping_key)
-        self.expect_node(mapping=True)
-
-    # Checkers.
-
-    def check_empty_sequence(self):
-        return (isinstance(self.event, SequenceStartEvent) and self.events
-                and isinstance(self.events[0], SequenceEndEvent))
-
-    def check_empty_mapping(self):
-        return (isinstance(self.event, MappingStartEvent) and self.events
-                and isinstance(self.events[0], MappingEndEvent))
-
-    def check_empty_document(self):
-        if not isinstance(self.event, DocumentStartEvent) or not self.events:
-            return False
-        event = self.events[0]
-        return (isinstance(event, ScalarEvent) and event.anchor is None
-                and event.tag is None and event.implicit and event.value == '')
-
-    def check_simple_key(self):
-        length = 0
-        if isinstance(self.event, NodeEvent) and self.event.anchor is not None:
-            if self.prepared_anchor is None:
-                self.prepared_anchor = self.prepare_anchor(self.event.anchor)
-            length += len(self.prepared_anchor)
-        if isinstance(self.event, (ScalarEvent, CollectionStartEvent))  \
-                and self.event.tag is not None:
-            if self.prepared_tag is None:
-                self.prepared_tag = self.prepare_tag(self.event.tag)
-            length += len(self.prepared_tag)
-        if isinstance(self.event, ScalarEvent):
-            if self.analysis is None:
-                self.analysis = self.analyze_scalar(self.event.value)
-            length += len(self.analysis.scalar)
-        return (length < 128 and (isinstance(self.event, AliasEvent)
-            or (isinstance(self.event, ScalarEvent)
-                    and not self.analysis.empty and not self.analysis.multiline)
-            or self.check_empty_sequence() or self.check_empty_mapping()))
-
-    # Anchor, Tag, and Scalar processors.
-
-    def process_anchor(self, indicator):
-        if self.event.anchor is None:
-            self.prepared_anchor = None
-            return
-        if self.prepared_anchor is None:
-            self.prepared_anchor = self.prepare_anchor(self.event.anchor)
-        if self.prepared_anchor:
-            self.write_indicator(indicator+self.prepared_anchor, True)
-        self.prepared_anchor = None
-
-    def process_tag(self):
-        tag = self.event.tag
-        if isinstance(self.event, ScalarEvent):
-            if self.style is None:
-                self.style = self.choose_scalar_style()
-            if ((not self.canonical or tag is None) and
-                ((self.style == '' and self.event.implicit[0])
-                        or (self.style != '' and self.event.implicit[1]))):
-                self.prepared_tag = None
-                return
-            if self.event.implicit[0] and tag is None:
-                tag = '!'
-                self.prepared_tag = None
-        else:
-            if (not self.canonical or tag is None) and self.event.implicit:
-                self.prepared_tag = None
-                return
-        if tag is None:
-            raise EmitterError("tag is not specified")
-        if self.prepared_tag is None:
-            self.prepared_tag = self.prepare_tag(tag)
-        if self.prepared_tag:
-            self.write_indicator(self.prepared_tag, True)
-        self.prepared_tag = None
-
-    def choose_scalar_style(self):
-        if self.analysis is None:
-            self.analysis = self.analyze_scalar(self.event.value)
-        if self.event.style == '"' or self.canonical:
-            return '"'
-        if not self.event.style and self.event.implicit[0]:
-            if (not (self.simple_key_context and
-                    (self.analysis.empty or self.analysis.multiline))
-                and (self.flow_level and self.analysis.allow_flow_plain
-                    or (not self.flow_level and self.analysis.allow_block_plain))):
-                return ''
-        if self.event.style and self.event.style in '|>':
-            if (not self.flow_level and not self.simple_key_context
-                    and self.analysis.allow_block):
-                return self.event.style
-        if not self.event.style or self.event.style == '\'':
-            if (self.analysis.allow_single_quoted and
-                    not (self.simple_key_context and self.analysis.multiline)):
-                return '\''
-        return '"'
-
-    def process_scalar(self):
-        if self.analysis is None:
-            self.analysis = self.analyze_scalar(self.event.value)
-        if self.style is None:
-            self.style = self.choose_scalar_style()
-        split = (not self.simple_key_context)
-        #if self.analysis.multiline and split    \
-        #        and (not self.style or self.style in '\'\"'):
-        #    self.write_indent()
-        if self.style == '"':
-            self.write_double_quoted(self.analysis.scalar, split)
-        elif self.style == '\'':
-            self.write_single_quoted(self.analysis.scalar, split)
-        elif self.style == '>':
-            self.write_folded(self.analysis.scalar)
-        elif self.style == '|':
-            self.write_literal(self.analysis.scalar)
-        else:
-            self.write_plain(self.analysis.scalar, split)
-        self.analysis = None
-        self.style = None
-
-    # Analyzers.
-
-    def prepare_version(self, version):
-        major, minor = version
-        if major != 1:
-            raise EmitterError("unsupported YAML version: %d.%d" % (major, minor))
-        return '%d.%d' % (major, minor)
-
-    def prepare_tag_handle(self, handle):
-        if not handle:
-            raise EmitterError("tag handle must not be empty")
-        if handle[0] != '!' or handle[-1] != '!':
-            raise EmitterError("tag handle must start and end with '!': %r" % handle)
-        for ch in handle[1:-1]:
-            if not ('0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'    \
-                    or ch in '-_'):
-                raise EmitterError("invalid character %r in the tag handle: %r"
-                        % (ch, handle))
-        return handle
-
-    def prepare_tag_prefix(self, prefix):
-        if not prefix:
-            raise EmitterError("tag prefix must not be empty")
-        chunks = []
-        start = end = 0
-        if prefix[0] == '!':
-            end = 1
-        while end < len(prefix):
-            ch = prefix[end]
-            if '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z' \
-                    or ch in '-;/?!:@&=+$,_.~*\'()[]':
-                end += 1
-            else:
-                if start < end:
-                    chunks.append(prefix[start:end])
-                start = end = end+1
-                data = ch.encode('utf-8')
-                for ch in data:
-                    chunks.append('%%%02X' % ord(ch))
-        if start < end:
-            chunks.append(prefix[start:end])
-        return ''.join(chunks)
-
-    def prepare_tag(self, tag):
-        if not tag:
-            raise EmitterError("tag must not be empty")
-        if tag == '!':
-            return tag
-        handle = None
-        suffix = tag
-        prefixes = sorted(self.tag_prefixes.keys())
-        for prefix in prefixes:
-            if tag.startswith(prefix)   \
-                    and (prefix == '!' or len(prefix) < len(tag)):
-                handle = self.tag_prefixes[prefix]
-                suffix = tag[len(prefix):]
-        chunks = []
-        start = end = 0
-        while end < len(suffix):
-            ch = suffix[end]
-            if '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z' \
-                    or ch in '-;/?:@&=+$,_.~*\'()[]'   \
-                    or (ch == '!' and handle != '!'):
-                end += 1
-            else:
-                if start < end:
-                    chunks.append(suffix[start:end])
-                start = end = end+1
-                data = ch.encode('utf-8')
-                for ch in data:
-                    chunks.append('%%%02X' % ord(ch))
-        if start < end:
-            chunks.append(suffix[start:end])
-        suffix_text = ''.join(chunks)
-        if handle:
-            return '%s%s' % (handle, suffix_text)
-        else:
-            return '!<%s>' % suffix_text
-
-    def prepare_anchor(self, anchor):
-        if not anchor:
-            raise EmitterError("anchor must not be empty")
-        for ch in anchor:
-            if not ('0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'    \
-                    or ch in '-_'):
-                raise EmitterError("invalid character %r in the anchor: %r"
-                        % (ch, anchor))
-        return anchor
-
-    def analyze_scalar(self, scalar):
-
-        # Empty scalar is a special case.
-        if not scalar:
-            return ScalarAnalysis(scalar=scalar, empty=True, multiline=False,
-                    allow_flow_plain=False, allow_block_plain=True,
-                    allow_single_quoted=True, allow_double_quoted=True,
-                    allow_block=False)
-
-        # Indicators and special characters.
-        block_indicators = False
-        flow_indicators = False
-        line_breaks = False
-        special_characters = False
-
-        # Important whitespace combinations.
-        leading_space = False
-        leading_break = False
-        trailing_space = False
-        trailing_break = False
-        break_space = False
-        space_break = False
-
-        # Check document indicators.
-        if scalar.startswith('---') or scalar.startswith('...'):
-            block_indicators = True
-            flow_indicators = True
-
-        # First character or preceded by a whitespace.
-        preceded_by_whitespace = True
-
-        # Last character or followed by a whitespace.
-        followed_by_whitespace = (len(scalar) == 1 or
-                scalar[1] in '\0 \t\r\n\x85\u2028\u2029')
-
-        # The previous character is a space.
-        previous_space = False
-
-        # The previous character is a break.
-        previous_break = False
-
-        index = 0
-        while index < len(scalar):
-            ch = scalar[index]
-
-            # Check for indicators.
-            if index == 0:
-                # Leading indicators are special characters.
-                if ch in '#,[]{}&*!|>\'\"%@`':
-                    flow_indicators = True
-                    block_indicators = True
-                if ch in '?:':
-                    flow_indicators = True
-                    if followed_by_whitespace:
-                        block_indicators = True
-                if ch == '-' and followed_by_whitespace:
-                    flow_indicators = True
-                    block_indicators = True
-            else:
-                # Some indicators cannot appear within a scalar as well.
-                if ch in ',?[]{}':
-                    flow_indicators = True
-                if ch == ':':
-                    flow_indicators = True
-                    if followed_by_whitespace:
-                        block_indicators = True
-                if ch == '#' and preceded_by_whitespace:
-                    flow_indicators = True
-                    block_indicators = True
-
-            # Check for line breaks, special, and unicode characters.
-            if ch in '\n\x85\u2028\u2029':
-                line_breaks = True
-            if not (ch == '\n' or '\x20' <= ch <= '\x7E'):
-                if (ch == '\x85' or '\xA0' <= ch <= '\uD7FF'
-                        or '\uE000' <= ch <= '\uFFFD'
-                        or '\U00010000' <= ch < '\U0010ffff') and ch != '\uFEFF':
-                    unicode_characters = True
-                    if not self.allow_unicode:
-                        special_characters = True
-                else:
-                    special_characters = True
-
-            # Detect important whitespace combinations.
-            if ch == ' ':
-                if index == 0:
-                    leading_space = True
-                if index == len(scalar)-1:
-                    trailing_space = True
-                if previous_break:
-                    break_space = True
-                previous_space = True
-                previous_break = False
-            elif ch in '\n\x85\u2028\u2029':
-                if index == 0:
-                    leading_break = True
-                if index == len(scalar)-1:
-                    trailing_break = True
-                if previous_space:
-                    space_break = True
-                previous_space = False
-                previous_break = True
-            else:
-                previous_space = False
-                previous_break = False
-
-            # Prepare for the next character.
-            index += 1
-            preceded_by_whitespace = (ch in '\0 \t\r\n\x85\u2028\u2029')
-            followed_by_whitespace = (index+1 >= len(scalar) or
-                    scalar[index+1] in '\0 \t\r\n\x85\u2028\u2029')
-
-        # Let's decide what styles are allowed.
-        allow_flow_plain = True
-        allow_block_plain = True
-        allow_single_quoted = True
-        allow_double_quoted = True
-        allow_block = True
-
-        # Leading and trailing whitespaces are bad for plain scalars.
-        if (leading_space or leading_break
-                or trailing_space or trailing_break):
-            allow_flow_plain = allow_block_plain = False
-
-        # We do not permit trailing spaces for block scalars.
-        if trailing_space:
-            allow_block = False
-
-        # Spaces at the beginning of a new line are only acceptable for block
-        # scalars.
-        if break_space:
-            allow_flow_plain = allow_block_plain = allow_single_quoted = False
-
-        # Spaces followed by breaks, as well as special character are only
-        # allowed for double quoted scalars.
-        if space_break or special_characters:
-            allow_flow_plain = allow_block_plain =  \
-            allow_single_quoted = allow_block = False
-
-        # Although the plain scalar writer supports breaks, we never emit
-        # multiline plain scalars.
-        if line_breaks:
-            allow_flow_plain = allow_block_plain = False
-
-        # Flow indicators are forbidden for flow plain scalars.
-        if flow_indicators:
-            allow_flow_plain = False
-
-        # Block indicators are forbidden for block plain scalars.
-        if block_indicators:
-            allow_block_plain = False
-
-        return ScalarAnalysis(scalar=scalar,
-                empty=False, multiline=line_breaks,
-                allow_flow_plain=allow_flow_plain,
-                allow_block_plain=allow_block_plain,
-                allow_single_quoted=allow_single_quoted,
-                allow_double_quoted=allow_double_quoted,
-                allow_block=allow_block)
-
-    # Writers.
-
-    def flush_stream(self):
-        if hasattr(self.stream, 'flush'):
-            self.stream.flush()
-
-    def write_stream_start(self):
-        # Write BOM if needed.
-        if self.encoding and self.encoding.startswith('utf-16'):
-            self.stream.write('\uFEFF'.encode(self.encoding))
-
-    def write_stream_end(self):
-        self.flush_stream()
-
-    def write_indicator(self, indicator, need_whitespace,
-            whitespace=False, indention=False):
-        if self.whitespace or not need_whitespace:
-            data = indicator
-        else:
-            data = ' '+indicator
-        self.whitespace = whitespace
-        self.indention = self.indention and indention
-        self.column += len(data)
-        self.open_ended = False
-        if self.encoding:
-            data = data.encode(self.encoding)
-        self.stream.write(data)
-
-    def write_indent(self):
-        indent = self.indent or 0
-        if not self.indention or self.column > indent   \
-                or (self.column == indent and not self.whitespace):
-            self.write_line_break()
-        if self.column < indent:
-            self.whitespace = True
-            data = ' '*(indent-self.column)
-            self.column = indent
-            if self.encoding:
-                data = data.encode(self.encoding)
-            self.stream.write(data)
-
-    def write_line_break(self, data=None):
-        if data is None:
-            data = self.best_line_break
-        self.whitespace = True
-        self.indention = True
-        self.line += 1
-        self.column = 0
-        if self.encoding:
-            data = data.encode(self.encoding)
-        self.stream.write(data)
-
-    def write_version_directive(self, version_text):
-        data = '%%YAML %s' % version_text
-        if self.encoding:
-            data = data.encode(self.encoding)
-        self.stream.write(data)
-        self.write_line_break()
-
-    def write_tag_directive(self, handle_text, prefix_text):
-        data = '%%TAG %s %s' % (handle_text, prefix_text)
-        if self.encoding:
-            data = data.encode(self.encoding)
-        self.stream.write(data)
-        self.write_line_break()
-
-    # Scalar streams.
-
-    def write_single_quoted(self, text, split=True):
-        self.write_indicator('\'', True)
-        spaces = False
-        breaks = False
-        start = end = 0
-        while end <= len(text):
-            ch = None
-            if end < len(text):
-                ch = text[end]
-            if spaces:
-                if ch is None or ch != ' ':
-                    if start+1 == end and self.column > self.best_width and split   \
-                            and start != 0 and end != len(text):
-                        self.write_indent()
-                    else:
-                        data = text[start:end]
-                        self.column += len(data)
-                        if self.encoding:
-                            data = data.encode(self.encoding)
-                        self.stream.write(data)
-                    start = end
-            elif breaks:
-                if ch is None or ch not in '\n\x85\u2028\u2029':
-                    if text[start] == '\n':
-                        self.write_line_break()
-                    for br in text[start:end]:
-                        if br == '\n':
-                            self.write_line_break()
-                        else:
-                            self.write_line_break(br)
-                    self.write_indent()
-                    start = end
-            else:
-                if ch is None or ch in ' \n\x85\u2028\u2029' or ch == '\'':
-                    if start < end:
-                        data = text[start:end]
-                        self.column += len(data)
-                        if self.encoding:
-                            data = data.encode(self.encoding)
-                        self.stream.write(data)
-                        start = end
-            if ch == '\'':
-                data = '\'\''
-                self.column += 2
-                if self.encoding:
-                    data = data.encode(self.encoding)
-                self.stream.write(data)
-                start = end + 1
-            if ch is not None:
-                spaces = (ch == ' ')
-                breaks = (ch in '\n\x85\u2028\u2029')
-            end += 1
-        self.write_indicator('\'', False)
-
-    ESCAPE_REPLACEMENTS = {
-        '\0':       '0',
-        '\x07':     'a',
-        '\x08':     'b',
-        '\x09':     't',
-        '\x0A':     'n',
-        '\x0B':     'v',
-        '\x0C':     'f',
-        '\x0D':     'r',
-        '\x1B':     'e',
-        '\"':       '\"',
-        '\\':       '\\',
-        '\x85':     'N',
-        '\xA0':     '_',
-        '\u2028':   'L',
-        '\u2029':   'P',
-    }
-
-    def write_double_quoted(self, text, split=True):
-        self.write_indicator('"', True)
-        start = end = 0
-        while end <= len(text):
-            ch = None
-            if end < len(text):
-                ch = text[end]
-            if ch is None or ch in '"\\\x85\u2028\u2029\uFEFF' \
-                    or not ('\x20' <= ch <= '\x7E'
-                        or (self.allow_unicode
-                            and ('\xA0' <= ch <= '\uD7FF'
-                                or '\uE000' <= ch <= '\uFFFD'))):
-                if start < end:
-                    data = text[start:end]
-                    self.column += len(data)
-                    if self.encoding:
-                        data = data.encode(self.encoding)
-                    self.stream.write(data)
-                    start = end
-                if ch is not None:
-                    if ch in self.ESCAPE_REPLACEMENTS:
-                        data = '\\'+self.ESCAPE_REPLACEMENTS[ch]
-                    elif ch <= '\xFF':
-                        data = '\\x%02X' % ord(ch)
-                    elif ch <= '\uFFFF':
-                        data = '\\u%04X' % ord(ch)
-                    else:
-                        data = '\\U%08X' % ord(ch)
-                    self.column += len(data)
-                    if self.encoding:
-                        data = data.encode(self.encoding)
-                    self.stream.write(data)
-                    start = end+1
-            if 0 < end < len(text)-1 and (ch == ' ' or start >= end)    \
-                    and self.column+(end-start) > self.best_width and split:
-                data = text[start:end]+'\\'
-                if start < end:
-                    start = end
-                self.column += len(data)
-                if self.encoding:
-                    data = data.encode(self.encoding)
-                self.stream.write(data)
-                self.write_indent()
-                self.whitespace = False
-                self.indention = False
-                if text[start] == ' ':
-                    data = '\\'
-                    self.column += len(data)
-                    if self.encoding:
-                        data = data.encode(self.encoding)
-                    self.stream.write(data)
-            end += 1
-        self.write_indicator('"', False)
-
-    def determine_block_hints(self, text):
-        hints = ''
-        if text:
-            if text[0] in ' \n\x85\u2028\u2029':
-                hints += str(self.best_indent)
-            if text[-1] not in '\n\x85\u2028\u2029':
-                hints += '-'
-            elif len(text) == 1 or text[-2] in '\n\x85\u2028\u2029':
-                hints += '+'
-        return hints
-
-    def write_folded(self, text):
-        hints = self.determine_block_hints(text)
-        self.write_indicator('>'+hints, True)
-        if hints[-1:] == '+':
-            self.open_ended = True
-        self.write_line_break()
-        leading_space = True
-        spaces = False
-        breaks = True
-        start = end = 0
-        while end <= len(text):
-            ch = None
-            if end < len(text):
-                ch = text[end]
-            if breaks:
-                if ch is None or ch not in '\n\x85\u2028\u2029':
-                    if not leading_space and ch is not None and ch != ' '   \
-                            and text[start] == '\n':
-                        self.write_line_break()
-                    leading_space = (ch == ' ')
-                    for br in text[start:end]:
-                        if br == '\n':
-                            self.write_line_break()
-                        else:
-                            self.write_line_break(br)
-                    if ch is not None:
-                        self.write_indent()
-                    start = end
-            elif spaces:
-                if ch != ' ':
-                    if start+1 == end and self.column > self.best_width:
-                        self.write_indent()
-                    else:
-                        data = text[start:end]
-                        self.column += len(data)
-                        if self.encoding:
-                            data = data.encode(self.encoding)
-                        self.stream.write(data)
-                    start = end
-            else:
-                if ch is None or ch in ' \n\x85\u2028\u2029':
-                    data = text[start:end]
-                    self.column += len(data)
-                    if self.encoding:
-                        data = data.encode(self.encoding)
-                    self.stream.write(data)
-                    if ch is None:
-                        self.write_line_break()
-                    start = end
-            if ch is not None:
-                breaks = (ch in '\n\x85\u2028\u2029')
-                spaces = (ch == ' ')
-            end += 1
-
-    def write_literal(self, text):
-        hints = self.determine_block_hints(text)
-        self.write_indicator('|'+hints, True)
-        if hints[-1:] == '+':
-            self.open_ended = True
-        self.write_line_break()
-        breaks = True
-        start = end = 0
-        while end <= len(text):
-            ch = None
-            if end < len(text):
-                ch = text[end]
-            if breaks:
-                if ch is None or ch not in '\n\x85\u2028\u2029':
-                    for br in text[start:end]:
-                        if br == '\n':
-                            self.write_line_break()
-                        else:
-                            self.write_line_break(br)
-                    if ch is not None:
-                        self.write_indent()
-                    start = end
-            else:
-                if ch is None or ch in '\n\x85\u2028\u2029':
-                    data = text[start:end]
-                    if self.encoding:
-                        data = data.encode(self.encoding)
-                    self.stream.write(data)
-                    if ch is None:
-                        self.write_line_break()
-                    start = end
-            if ch is not None:
-                breaks = (ch in '\n\x85\u2028\u2029')
-            end += 1
-
-    def write_plain(self, text, split=True):
-        if self.root_context:
-            self.open_ended = True
-        if not text:
-            return
-        if not self.whitespace:
-            data = ' '
-            self.column += len(data)
-            if self.encoding:
-                data = data.encode(self.encoding)
-            self.stream.write(data)
-        self.whitespace = False
-        self.indention = False
-        spaces = False
-        breaks = False
-        start = end = 0
-        while end <= len(text):
-            ch = None
-            if end < len(text):
-                ch = text[end]
-            if spaces:
-                if ch != ' ':
-                    if start+1 == end and self.column > self.best_width and split:
-                        self.write_indent()
-                        self.whitespace = False
-                        self.indention = False
-                    else:
-                        data = text[start:end]
-                        self.column += len(data)
-                        if self.encoding:
-                            data = data.encode(self.encoding)
-                        self.stream.write(data)
-                    start = end
-            elif breaks:
-                if ch not in '\n\x85\u2028\u2029':
-                    if text[start] == '\n':
-                        self.write_line_break()
-                    for br in text[start:end]:
-                        if br == '\n':
-                            self.write_line_break()
-                        else:
-                            self.write_line_break(br)
-                    self.write_indent()
-                    self.whitespace = False
-                    self.indention = False
-                    start = end
-            else:
-                if ch is None or ch in ' \n\x85\u2028\u2029':
-                    data = text[start:end]
-                    self.column += len(data)
-                    if self.encoding:
-                        data = data.encode(self.encoding)
-                    self.stream.write(data)
-                    start = end
-            if ch is not None:
-                spaces = (ch == ' ')
-                breaks = (ch in '\n\x85\u2028\u2029')
-            end += 1
diff --git a/lib3/yaml/error.py b/lib3/yaml/error.py
deleted file mode 100644
index b796b4d..0000000
--- a/lib3/yaml/error.py
+++ /dev/null
@@ -1,75 +0,0 @@
-
-__all__ = ['Mark', 'YAMLError', 'MarkedYAMLError']
-
-class Mark:
-
-    def __init__(self, name, index, line, column, buffer, pointer):
-        self.name = name
-        self.index = index
-        self.line = line
-        self.column = column
-        self.buffer = buffer
-        self.pointer = pointer
-
-    def get_snippet(self, indent=4, max_length=75):
-        if self.buffer is None:
-            return None
-        head = ''
-        start = self.pointer
-        while start > 0 and self.buffer[start-1] not in '\0\r\n\x85\u2028\u2029':
-            start -= 1
-            if self.pointer-start > max_length/2-1:
-                head = ' ... '
-                start += 5
-                break
-        tail = ''
-        end = self.pointer
-        while end < len(self.buffer) and self.buffer[end] not in '\0\r\n\x85\u2028\u2029':
-            end += 1
-            if end-self.pointer > max_length/2-1:
-                tail = ' ... '
-                end -= 5
-                break
-        snippet = self.buffer[start:end]
-        return ' '*indent + head + snippet + tail + '\n'  \
-                + ' '*(indent+self.pointer-start+len(head)) + '^'
-
-    def __str__(self):
-        snippet = self.get_snippet()
-        where = "  in \"%s\", line %d, column %d"   \
-                % (self.name, self.line+1, self.column+1)
-        if snippet is not None:
-            where += ":\n"+snippet
-        return where
-
-class YAMLError(Exception):
-    pass
-
-class MarkedYAMLError(YAMLError):
-
-    def __init__(self, context=None, context_mark=None,
-            problem=None, problem_mark=None, note=None):
-        self.context = context
-        self.context_mark = context_mark
-        self.problem = problem
-        self.problem_mark = problem_mark
-        self.note = note
-
-    def __str__(self):
-        lines = []
-        if self.context is not None:
-            lines.append(self.context)
-        if self.context_mark is not None  \
-            and (self.problem is None or self.problem_mark is None
-                    or self.context_mark.name != self.problem_mark.name
-                    or self.context_mark.line != self.problem_mark.line
-                    or self.context_mark.column != self.problem_mark.column):
-            lines.append(str(self.context_mark))
-        if self.problem is not None:
-            lines.append(self.problem)
-        if self.problem_mark is not None:
-            lines.append(str(self.problem_mark))
-        if self.note is not None:
-            lines.append(self.note)
-        return '\n'.join(lines)
-
diff --git a/lib3/yaml/events.py b/lib3/yaml/events.py
deleted file mode 100644
index f79ad38..0000000
--- a/lib3/yaml/events.py
+++ /dev/null
@@ -1,86 +0,0 @@
-
-# Abstract classes.
-
-class Event(object):
-    def __init__(self, start_mark=None, end_mark=None):
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-    def __repr__(self):
-        attributes = [key for key in ['anchor', 'tag', 'implicit', 'value']
-                if hasattr(self, key)]
-        arguments = ', '.join(['%s=%r' % (key, getattr(self, key))
-                for key in attributes])
-        return '%s(%s)' % (self.__class__.__name__, arguments)
-
-class NodeEvent(Event):
-    def __init__(self, anchor, start_mark=None, end_mark=None):
-        self.anchor = anchor
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-
-class CollectionStartEvent(NodeEvent):
-    def __init__(self, anchor, tag, implicit, start_mark=None, end_mark=None,
-            flow_style=None):
-        self.anchor = anchor
-        self.tag = tag
-        self.implicit = implicit
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.flow_style = flow_style
-
-class CollectionEndEvent(Event):
-    pass
-
-# Implementations.
-
-class StreamStartEvent(Event):
-    def __init__(self, start_mark=None, end_mark=None, encoding=None):
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.encoding = encoding
-
-class StreamEndEvent(Event):
-    pass
-
-class DocumentStartEvent(Event):
-    def __init__(self, start_mark=None, end_mark=None,
-            explicit=None, version=None, tags=None):
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.explicit = explicit
-        self.version = version
-        self.tags = tags
-
-class DocumentEndEvent(Event):
-    def __init__(self, start_mark=None, end_mark=None,
-            explicit=None):
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.explicit = explicit
-
-class AliasEvent(NodeEvent):
-    pass
-
-class ScalarEvent(NodeEvent):
-    def __init__(self, anchor, tag, implicit, value,
-            start_mark=None, end_mark=None, style=None):
-        self.anchor = anchor
-        self.tag = tag
-        self.implicit = implicit
-        self.value = value
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.style = style
-
-class SequenceStartEvent(CollectionStartEvent):
-    pass
-
-class SequenceEndEvent(CollectionEndEvent):
-    pass
-
-class MappingStartEvent(CollectionStartEvent):
-    pass
-
-class MappingEndEvent(CollectionEndEvent):
-    pass
-
diff --git a/lib3/yaml/loader.py b/lib3/yaml/loader.py
deleted file mode 100644
index 16e9fab..0000000
--- a/lib3/yaml/loader.py
+++ /dev/null
@@ -1,40 +0,0 @@
-
-__all__ = ['BaseLoader', 'SafeLoader', 'Loader', 'DangerLoader']
-
-from .reader import *
-from .scanner import *
-from .parser import *
-from .composer import *
-from .constructor import *
-from .resolver import *
-
-class BaseLoader(Reader, Scanner, Parser, Composer, BaseConstructor, BaseResolver):
-
-    def __init__(self, stream):
-        Reader.__init__(self, stream)
-        Scanner.__init__(self)
-        Parser.__init__(self)
-        Composer.__init__(self)
-        BaseConstructor.__init__(self)
-        BaseResolver.__init__(self)
-
-class Loader(Reader, Scanner, Parser, Composer, SafeConstructor, Resolver):
-
-    def __init__(self, stream):
-        Reader.__init__(self, stream)
-        Scanner.__init__(self)
-        Parser.__init__(self)
-        Composer.__init__(self)
-        SafeConstructor.__init__(self)
-        Resolver.__init__(self)
-SafeLoader = Loader
-
-class DangerLoader(Reader, Scanner, Parser, Composer, Constructor, Resolver):
-
-    def __init__(self, stream):
-        Reader.__init__(self, stream)
-        Scanner.__init__(self)
-        Parser.__init__(self)
-        Composer.__init__(self)
-        Constructor.__init__(self)
-        Resolver.__init__(self)
diff --git a/lib3/yaml/nodes.py b/lib3/yaml/nodes.py
deleted file mode 100644
index c4f070c..0000000
--- a/lib3/yaml/nodes.py
+++ /dev/null
@@ -1,49 +0,0 @@
-
-class Node(object):
-    def __init__(self, tag, value, start_mark, end_mark):
-        self.tag = tag
-        self.value = value
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-    def __repr__(self):
-        value = self.value
-        #if isinstance(value, list):
-        #    if len(value) == 0:
-        #        value = '<empty>'
-        #    elif len(value) == 1:
-        #        value = '<1 item>'
-        #    else:
-        #        value = '<%d items>' % len(value)
-        #else:
-        #    if len(value) > 75:
-        #        value = repr(value[:70]+u' ... ')
-        #    else:
-        #        value = repr(value)
-        value = repr(value)
-        return '%s(tag=%r, value=%s)' % (self.__class__.__name__, self.tag, value)
-
-class ScalarNode(Node):
-    id = 'scalar'
-    def __init__(self, tag, value,
-            start_mark=None, end_mark=None, style=None):
-        self.tag = tag
-        self.value = value
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.style = style
-
-class CollectionNode(Node):
-    def __init__(self, tag, value,
-            start_mark=None, end_mark=None, flow_style=None):
-        self.tag = tag
-        self.value = value
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.flow_style = flow_style
-
-class SequenceNode(CollectionNode):
-    id = 'sequence'
-
-class MappingNode(CollectionNode):
-    id = 'mapping'
-
diff --git a/lib3/yaml/parser.py b/lib3/yaml/parser.py
deleted file mode 100644
index 13a5995..0000000
--- a/lib3/yaml/parser.py
+++ /dev/null
@@ -1,589 +0,0 @@
-
-# The following YAML grammar is LL(1) and is parsed by a recursive descent
-# parser.
-#
-# stream            ::= STREAM-START implicit_document? explicit_document* STREAM-END
-# implicit_document ::= block_node DOCUMENT-END*
-# explicit_document ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
-# block_node_or_indentless_sequence ::=
-#                       ALIAS
-#                       | properties (block_content | indentless_block_sequence)?
-#                       | block_content
-#                       | indentless_block_sequence
-# block_node        ::= ALIAS
-#                       | properties block_content?
-#                       | block_content
-# flow_node         ::= ALIAS
-#                       | properties flow_content?
-#                       | flow_content
-# properties        ::= TAG ANCHOR? | ANCHOR TAG?
-# block_content     ::= block_collection | flow_collection | SCALAR
-# flow_content      ::= flow_collection | SCALAR
-# block_collection  ::= block_sequence | block_mapping
-# flow_collection   ::= flow_sequence | flow_mapping
-# block_sequence    ::= BLOCK-SEQUENCE-START (BLOCK-ENTRY block_node?)* BLOCK-END
-# indentless_sequence   ::= (BLOCK-ENTRY block_node?)+
-# block_mapping     ::= BLOCK-MAPPING_START
-#                       ((KEY block_node_or_indentless_sequence?)?
-#                       (VALUE block_node_or_indentless_sequence?)?)*
-#                       BLOCK-END
-# flow_sequence     ::= FLOW-SEQUENCE-START
-#                       (flow_sequence_entry FLOW-ENTRY)*
-#                       flow_sequence_entry?
-#                       FLOW-SEQUENCE-END
-# flow_sequence_entry   ::= flow_node | KEY flow_node? (VALUE flow_node?)?
-# flow_mapping      ::= FLOW-MAPPING-START
-#                       (flow_mapping_entry FLOW-ENTRY)*
-#                       flow_mapping_entry?
-#                       FLOW-MAPPING-END
-# flow_mapping_entry    ::= flow_node | KEY flow_node? (VALUE flow_node?)?
-#
-# FIRST sets:
-#
-# stream: { STREAM-START }
-# explicit_document: { DIRECTIVE DOCUMENT-START }
-# implicit_document: FIRST(block_node)
-# block_node: { ALIAS TAG ANCHOR SCALAR BLOCK-SEQUENCE-START BLOCK-MAPPING-START FLOW-SEQUENCE-START FLOW-MAPPING-START }
-# flow_node: { ALIAS ANCHOR TAG SCALAR FLOW-SEQUENCE-START FLOW-MAPPING-START }
-# block_content: { BLOCK-SEQUENCE-START BLOCK-MAPPING-START FLOW-SEQUENCE-START FLOW-MAPPING-START SCALAR }
-# flow_content: { FLOW-SEQUENCE-START FLOW-MAPPING-START SCALAR }
-# block_collection: { BLOCK-SEQUENCE-START BLOCK-MAPPING-START }
-# flow_collection: { FLOW-SEQUENCE-START FLOW-MAPPING-START }
-# block_sequence: { BLOCK-SEQUENCE-START }
-# block_mapping: { BLOCK-MAPPING-START }
-# block_node_or_indentless_sequence: { ALIAS ANCHOR TAG SCALAR BLOCK-SEQUENCE-START BLOCK-MAPPING-START FLOW-SEQUENCE-START FLOW-MAPPING-START BLOCK-ENTRY }
-# indentless_sequence: { ENTRY }
-# flow_collection: { FLOW-SEQUENCE-START FLOW-MAPPING-START }
-# flow_sequence: { FLOW-SEQUENCE-START }
-# flow_mapping: { FLOW-MAPPING-START }
-# flow_sequence_entry: { ALIAS ANCHOR TAG SCALAR FLOW-SEQUENCE-START FLOW-MAPPING-START KEY }
-# flow_mapping_entry: { ALIAS ANCHOR TAG SCALAR FLOW-SEQUENCE-START FLOW-MAPPING-START KEY }
-
-__all__ = ['Parser', 'ParserError']
-
-from .error import MarkedYAMLError
-from .tokens import *
-from .events import *
-from .scanner import *
-
-class ParserError(MarkedYAMLError):
-    pass
-
-class Parser:
-    # Since writing a recursive-descendant parser is a straightforward task, we
-    # do not give many comments here.
-
-    DEFAULT_TAGS = {
-        '!':   '!',
-        '!!':  'tag:yaml.org,2002:',
-    }
-
-    def __init__(self):
-        self.current_event = None
-        self.yaml_version = None
-        self.tag_handles = {}
-        self.states = []
-        self.marks = []
-        self.state = self.parse_stream_start
-
-    def dispose(self):
-        # Reset the state attributes (to clear self-references)
-        self.states = []
-        self.state = None
-
-    def check_event(self, *choices):
-        # Check the type of the next event.
-        if self.current_event is None:
-            if self.state:
-                self.current_event = self.state()
-        if self.current_event is not None:
-            if not choices:
-                return True
-            for choice in choices:
-                if isinstance(self.current_event, choice):
-                    return True
-        return False
-
-    def peek_event(self):
-        # Get the next event.
-        if self.current_event is None:
-            if self.state:
-                self.current_event = self.state()
-        return self.current_event
-
-    def get_event(self):
-        # Get the next event and proceed further.
-        if self.current_event is None:
-            if self.state:
-                self.current_event = self.state()
-        value = self.current_event
-        self.current_event = None
-        return value
-
-    # stream    ::= STREAM-START implicit_document? explicit_document* STREAM-END
-    # implicit_document ::= block_node DOCUMENT-END*
-    # explicit_document ::= DIRECTIVE* DOCUMENT-START block_node? DOCUMENT-END*
-
-    def parse_stream_start(self):
-
-        # Parse the stream start.
-        token = self.get_token()
-        event = StreamStartEvent(token.start_mark, token.end_mark,
-                encoding=token.encoding)
-
-        # Prepare the next state.
-        self.state = self.parse_implicit_document_start
-
-        return event
-
-    def parse_implicit_document_start(self):
-
-        # Parse an implicit document.
-        if not self.check_token(DirectiveToken, DocumentStartToken,
-                StreamEndToken):
-            self.tag_handles = self.DEFAULT_TAGS
-            token = self.peek_token()
-            start_mark = end_mark = token.start_mark
-            event = DocumentStartEvent(start_mark, end_mark,
-                    explicit=False)
-
-            # Prepare the next state.
-            self.states.append(self.parse_document_end)
-            self.state = self.parse_block_node
-
-            return event
-
-        else:
-            return self.parse_document_start()
-
-    def parse_document_start(self):
-
-        # Parse any extra document end indicators.
-        while self.check_token(DocumentEndToken):
-            self.get_token()
-
-        # Parse an explicit document.
-        if not self.check_token(StreamEndToken):
-            token = self.peek_token()
-            start_mark = token.start_mark
-            version, tags = self.process_directives()
-            if not self.check_token(DocumentStartToken):
-                raise ParserError(None, None,
-                        "expected '<document start>', but found %r"
-                        % self.peek_token().id,
-                        self.peek_token().start_mark)
-            token = self.get_token()
-            end_mark = token.end_mark
-            event = DocumentStartEvent(start_mark, end_mark,
-                    explicit=True, version=version, tags=tags)
-            self.states.append(self.parse_document_end)
-            self.state = self.parse_document_content
-        else:
-            # Parse the end of the stream.
-            token = self.get_token()
-            event = StreamEndEvent(token.start_mark, token.end_mark)
-            assert not self.states
-            assert not self.marks
-            self.state = None
-        return event
-
-    def parse_document_end(self):
-
-        # Parse the document end.
-        token = self.peek_token()
-        start_mark = end_mark = token.start_mark
-        explicit = False
-        if self.check_token(DocumentEndToken):
-            token = self.get_token()
-            end_mark = token.end_mark
-            explicit = True
-        event = DocumentEndEvent(start_mark, end_mark,
-                explicit=explicit)
-
-        # Prepare the next state.
-        self.state = self.parse_document_start
-
-        return event
-
-    def parse_document_content(self):
-        if self.check_token(DirectiveToken,
-                DocumentStartToken, DocumentEndToken, StreamEndToken):
-            event = self.process_empty_scalar(self.peek_token().start_mark)
-            self.state = self.states.pop()
-            return event
-        else:
-            return self.parse_block_node()
-
-    def process_directives(self):
-        self.yaml_version = None
-        self.tag_handles = {}
-        while self.check_token(DirectiveToken):
-            token = self.get_token()
-            if token.name == 'YAML':
-                if self.yaml_version is not None:
-                    raise ParserError(None, None,
-                            "found duplicate YAML directive", token.start_mark)
-                major, minor = token.value
-                if major != 1:
-                    raise ParserError(None, None,
-                            "found incompatible YAML document (version 1.* is required)",
-                            token.start_mark)
-                self.yaml_version = token.value
-            elif token.name == 'TAG':
-                handle, prefix = token.value
-                if handle in self.tag_handles:
-                    raise ParserError(None, None,
-                            "duplicate tag handle %r" % handle,
-                            token.start_mark)
-                self.tag_handles[handle] = prefix
-        if self.tag_handles:
-            value = self.yaml_version, self.tag_handles.copy()
-        else:
-            value = self.yaml_version, None
-        for key in self.DEFAULT_TAGS:
-            if key not in self.tag_handles:
-                self.tag_handles[key] = self.DEFAULT_TAGS[key]
-        return value
-
-    # block_node_or_indentless_sequence ::= ALIAS
-    #               | properties (block_content | indentless_block_sequence)?
-    #               | block_content
-    #               | indentless_block_sequence
-    # block_node    ::= ALIAS
-    #                   | properties block_content?
-    #                   | block_content
-    # flow_node     ::= ALIAS
-    #                   | properties flow_content?
-    #                   | flow_content
-    # properties    ::= TAG ANCHOR? | ANCHOR TAG?
-    # block_content     ::= block_collection | flow_collection | SCALAR
-    # flow_content      ::= flow_collection | SCALAR
-    # block_collection  ::= block_sequence | block_mapping
-    # flow_collection   ::= flow_sequence | flow_mapping
-
-    def parse_block_node(self):
-        return self.parse_node(block=True)
-
-    def parse_flow_node(self):
-        return self.parse_node()
-
-    def parse_block_node_or_indentless_sequence(self):
-        return self.parse_node(block=True, indentless_sequence=True)
-
-    def parse_node(self, block=False, indentless_sequence=False):
-        if self.check_token(AliasToken):
-            token = self.get_token()
-            event = AliasEvent(token.value, token.start_mark, token.end_mark)
-            self.state = self.states.pop()
-        else:
-            anchor = None
-            tag = None
-            start_mark = end_mark = tag_mark = None
-            if self.check_token(AnchorToken):
-                token = self.get_token()
-                start_mark = token.start_mark
-                end_mark = token.end_mark
-                anchor = token.value
-                if self.check_token(TagToken):
-                    token = self.get_token()
-                    tag_mark = token.start_mark
-                    end_mark = token.end_mark
-                    tag = token.value
-            elif self.check_token(TagToken):
-                token = self.get_token()
-                start_mark = tag_mark = token.start_mark
-                end_mark = token.end_mark
-                tag = token.value
-                if self.check_token(AnchorToken):
-                    token = self.get_token()
-                    end_mark = token.end_mark
-                    anchor = token.value
-            if tag is not None:
-                handle, suffix = tag
-                if handle is not None:
-                    if handle not in self.tag_handles:
-                        raise ParserError("while parsing a node", start_mark,
-                                "found undefined tag handle %r" % handle,
-                                tag_mark)
-                    tag = self.tag_handles[handle]+suffix
-                else:
-                    tag = suffix
-            #if tag == '!':
-            #    raise ParserError("while parsing a node", start_mark,
-            #            "found non-specific tag '!'", tag_mark,
-            #            "Please check 'http://pyyaml.org/wiki/YAMLNonSpecificTag' and share your opinion.")
-            if start_mark is None:
-                start_mark = end_mark = self.peek_token().start_mark
-            event = None
-            implicit = (tag is None or tag == '!')
-            if indentless_sequence and self.check_token(BlockEntryToken):
-                end_mark = self.peek_token().end_mark
-                event = SequenceStartEvent(anchor, tag, implicit,
-                        start_mark, end_mark)
-                self.state = self.parse_indentless_sequence_entry
-            else:
-                if self.check_token(ScalarToken):
-                    token = self.get_token()
-                    end_mark = token.end_mark
-                    if (token.plain and tag is None) or tag == '!':
-                        implicit = (True, False)
-                    elif tag is None:
-                        implicit = (False, True)
-                    else:
-                        implicit = (False, False)
-                    event = ScalarEvent(anchor, tag, implicit, token.value,
-                            start_mark, end_mark, style=token.style)
-                    self.state = self.states.pop()
-                elif self.check_token(FlowSequenceStartToken):
-                    end_mark = self.peek_token().end_mark
-                    event = SequenceStartEvent(anchor, tag, implicit,
-                            start_mark, end_mark, flow_style=True)
-                    self.state = self.parse_flow_sequence_first_entry
-                elif self.check_token(FlowMappingStartToken):
-                    end_mark = self.peek_token().end_mark
-                    event = MappingStartEvent(anchor, tag, implicit,
-                            start_mark, end_mark, flow_style=True)
-                    self.state = self.parse_flow_mapping_first_key
-                elif block and self.check_token(BlockSequenceStartToken):
-                    end_mark = self.peek_token().start_mark
-                    event = SequenceStartEvent(anchor, tag, implicit,
-                            start_mark, end_mark, flow_style=False)
-                    self.state = self.parse_block_sequence_first_entry
-                elif block and self.check_token(BlockMappingStartToken):
-                    end_mark = self.peek_token().start_mark
-                    event = MappingStartEvent(anchor, tag, implicit,
-                            start_mark, end_mark, flow_style=False)
-                    self.state = self.parse_block_mapping_first_key
-                elif anchor is not None or tag is not None:
-                    # Empty scalars are allowed even if a tag or an anchor is
-                    # specified.
-                    event = ScalarEvent(anchor, tag, (implicit, False), '',
-                            start_mark, end_mark)
-                    self.state = self.states.pop()
-                else:
-                    if block:
-                        node = 'block'
-                    else:
-                        node = 'flow'
-                    token = self.peek_token()
-                    raise ParserError("while parsing a %s node" % node, start_mark,
-                            "expected the node content, but found %r" % token.id,
-                            token.start_mark)
-        return event
-
-    # block_sequence ::= BLOCK-SEQUENCE-START (BLOCK-ENTRY block_node?)* BLOCK-END
-
-    def parse_block_sequence_first_entry(self):
-        token = self.get_token()
-        self.marks.append(token.start_mark)
-        return self.parse_block_sequence_entry()
-
-    def parse_block_sequence_entry(self):
-        if self.check_token(BlockEntryToken):
-            token = self.get_token()
-            if not self.check_token(BlockEntryToken, BlockEndToken):
-                self.states.append(self.parse_block_sequence_entry)
-                return self.parse_block_node()
-            else:
-                self.state = self.parse_block_sequence_entry
-                return self.process_empty_scalar(token.end_mark)
-        if not self.check_token(BlockEndToken):
-            token = self.peek_token()
-            raise ParserError("while parsing a block collection", self.marks[-1],
-                    "expected <block end>, but found %r" % token.id, token.start_mark)
-        token = self.get_token()
-        event = SequenceEndEvent(token.start_mark, token.end_mark)
-        self.state = self.states.pop()
-        self.marks.pop()
-        return event
-
-    # indentless_sequence ::= (BLOCK-ENTRY block_node?)+
-
-    def parse_indentless_sequence_entry(self):
-        if self.check_token(BlockEntryToken):
-            token = self.get_token()
-            if not self.check_token(BlockEntryToken,
-                    KeyToken, ValueToken, BlockEndToken):
-                self.states.append(self.parse_indentless_sequence_entry)
-                return self.parse_block_node()
-            else:
-                self.state = self.parse_indentless_sequence_entry
-                return self.process_empty_scalar(token.end_mark)
-        token = self.peek_token()
-        event = SequenceEndEvent(token.start_mark, token.start_mark)
-        self.state = self.states.pop()
-        return event
-
-    # block_mapping     ::= BLOCK-MAPPING_START
-    #                       ((KEY block_node_or_indentless_sequence?)?
-    #                       (VALUE block_node_or_indentless_sequence?)?)*
-    #                       BLOCK-END
-
-    def parse_block_mapping_first_key(self):
-        token = self.get_token()
-        self.marks.append(token.start_mark)
-        return self.parse_block_mapping_key()
-
-    def parse_block_mapping_key(self):
-        if self.check_token(KeyToken):
-            token = self.get_token()
-            if not self.check_token(KeyToken, ValueToken, BlockEndToken):
-                self.states.append(self.parse_block_mapping_value)
-                return self.parse_block_node_or_indentless_sequence()
-            else:
-                self.state = self.parse_block_mapping_value
-                return self.process_empty_scalar(token.end_mark)
-        if not self.check_token(BlockEndToken):
-            token = self.peek_token()
-            raise ParserError("while parsing a block mapping", self.marks[-1],
-                    "expected <block end>, but found %r" % token.id, token.start_mark)
-        token = self.get_token()
-        event = MappingEndEvent(token.start_mark, token.end_mark)
-        self.state = self.states.pop()
-        self.marks.pop()
-        return event
-
-    def parse_block_mapping_value(self):
-        if self.check_token(ValueToken):
-            token = self.get_token()
-            if not self.check_token(KeyToken, ValueToken, BlockEndToken):
-                self.states.append(self.parse_block_mapping_key)
-                return self.parse_block_node_or_indentless_sequence()
-            else:
-                self.state = self.parse_block_mapping_key
-                return self.process_empty_scalar(token.end_mark)
-        else:
-            self.state = self.parse_block_mapping_key
-            token = self.peek_token()
-            return self.process_empty_scalar(token.start_mark)
-
-    # flow_sequence     ::= FLOW-SEQUENCE-START
-    #                       (flow_sequence_entry FLOW-ENTRY)*
-    #                       flow_sequence_entry?
-    #                       FLOW-SEQUENCE-END
-    # flow_sequence_entry   ::= flow_node | KEY flow_node? (VALUE flow_node?)?
-    #
-    # Note that while production rules for both flow_sequence_entry and
-    # flow_mapping_entry are equal, their interpretations are different.
-    # For `flow_sequence_entry`, the part `KEY flow_node? (VALUE flow_node?)?`
-    # generate an inline mapping (set syntax).
-
-    def parse_flow_sequence_first_entry(self):
-        token = self.get_token()
-        self.marks.append(token.start_mark)
-        return self.parse_flow_sequence_entry(first=True)
-
-    def parse_flow_sequence_entry(self, first=False):
-        if not self.check_token(FlowSequenceEndToken):
-            if not first:
-                if self.check_token(FlowEntryToken):
-                    self.get_token()
-                else:
-                    token = self.peek_token()
-                    raise ParserError("while parsing a flow sequence", self.marks[-1],
-                            "expected ',' or ']', but got %r" % token.id, token.start_mark)
-            
-            if self.check_token(KeyToken):
-                token = self.peek_token()
-                event = MappingStartEvent(None, None, True,
-                        token.start_mark, token.end_mark,
-                        flow_style=True)
-                self.state = self.parse_flow_sequence_entry_mapping_key
-                return event
-            elif not self.check_token(FlowSequenceEndToken):
-                self.states.append(self.parse_flow_sequence_entry)
-                return self.parse_flow_node()
-        token = self.get_token()
-        event = SequenceEndEvent(token.start_mark, token.end_mark)
-        self.state = self.states.pop()
-        self.marks.pop()
-        return event
-
-    def parse_flow_sequence_entry_mapping_key(self):
-        token = self.get_token()
-        if not self.check_token(ValueToken,
-                FlowEntryToken, FlowSequenceEndToken):
-            self.states.append(self.parse_flow_sequence_entry_mapping_value)
-            return self.parse_flow_node()
-        else:
-            self.state = self.parse_flow_sequence_entry_mapping_value
-            return self.process_empty_scalar(token.end_mark)
-
-    def parse_flow_sequence_entry_mapping_value(self):
-        if self.check_token(ValueToken):
-            token = self.get_token()
-            if not self.check_token(FlowEntryToken, FlowSequenceEndToken):
-                self.states.append(self.parse_flow_sequence_entry_mapping_end)
-                return self.parse_flow_node()
-            else:
-                self.state = self.parse_flow_sequence_entry_mapping_end
-                return self.process_empty_scalar(token.end_mark)
-        else:
-            self.state = self.parse_flow_sequence_entry_mapping_end
-            token = self.peek_token()
-            return self.process_empty_scalar(token.start_mark)
-
-    def parse_flow_sequence_entry_mapping_end(self):
-        self.state = self.parse_flow_sequence_entry
-        token = self.peek_token()
-        return MappingEndEvent(token.start_mark, token.start_mark)
-
-    # flow_mapping  ::= FLOW-MAPPING-START
-    #                   (flow_mapping_entry FLOW-ENTRY)*
-    #                   flow_mapping_entry?
-    #                   FLOW-MAPPING-END
-    # flow_mapping_entry    ::= flow_node | KEY flow_node? (VALUE flow_node?)?
-
-    def parse_flow_mapping_first_key(self):
-        token = self.get_token()
-        self.marks.append(token.start_mark)
-        return self.parse_flow_mapping_key(first=True)
-
-    def parse_flow_mapping_key(self, first=False):
-        if not self.check_token(FlowMappingEndToken):
-            if not first:
-                if self.check_token(FlowEntryToken):
-                    self.get_token()
-                else:
-                    token = self.peek_token()
-                    raise ParserError("while parsing a flow mapping", self.marks[-1],
-                            "expected ',' or '}', but got %r" % token.id, token.start_mark)
-            if self.check_token(KeyToken):
-                token = self.get_token()
-                if not self.check_token(ValueToken,
-                        FlowEntryToken, FlowMappingEndToken):
-                    self.states.append(self.parse_flow_mapping_value)
-                    return self.parse_flow_node()
-                else:
-                    self.state = self.parse_flow_mapping_value
-                    return self.process_empty_scalar(token.end_mark)
-            elif not self.check_token(FlowMappingEndToken):
-                self.states.append(self.parse_flow_mapping_empty_value)
-                return self.parse_flow_node()
-        token = self.get_token()
-        event = MappingEndEvent(token.start_mark, token.end_mark)
-        self.state = self.states.pop()
-        self.marks.pop()
-        return event
-
-    def parse_flow_mapping_value(self):
-        if self.check_token(ValueToken):
-            token = self.get_token()
-            if not self.check_token(FlowEntryToken, FlowMappingEndToken):
-                self.states.append(self.parse_flow_mapping_key)
-                return self.parse_flow_node()
-            else:
-                self.state = self.parse_flow_mapping_key
-                return self.process_empty_scalar(token.end_mark)
-        else:
-            self.state = self.parse_flow_mapping_key
-            token = self.peek_token()
-            return self.process_empty_scalar(token.start_mark)
-
-    def parse_flow_mapping_empty_value(self):
-        self.state = self.parse_flow_mapping_key
-        return self.process_empty_scalar(self.peek_token().start_mark)
-
-    def process_empty_scalar(self, mark):
-        return ScalarEvent(None, None, (True, False), '', mark, mark)
-
diff --git a/lib3/yaml/reader.py b/lib3/yaml/reader.py
deleted file mode 100644
index 376b9a3..0000000
--- a/lib3/yaml/reader.py
+++ /dev/null
@@ -1,191 +0,0 @@
-# This module contains abstractions for the input stream. You don't have to
-# looks further, there are no pretty code.
-#
-# We define two classes here.
-#
-#   Mark(source, line, column)
-# It's just a record and its only use is producing nice error messages.
-# Parser does not use it for any other purposes.
-#
-#   Reader(source, data)
-# Reader determines the encoding of `data` and converts it to unicode.
-# Reader provides the following methods and attributes:
-#   reader.peek(length=1) - return the next `length` characters
-#   reader.forward(length=1) - move the current position to `length` characters.
-#   reader.index - the number of the current character.
-#   reader.line, stream.column - the line and the column of the current character.
-
-__all__ = ['Reader', 'ReaderError']
-
-from .error import YAMLError, Mark
-
-import codecs, re
-
-class ReaderError(YAMLError):
-
-    def __init__(self, name, position, character, encoding, reason):
-        self.name = name
-        self.character = character
-        self.position = position
-        self.encoding = encoding
-        self.reason = reason
-
-    def __str__(self):
-        if isinstance(self.character, bytes):
-            return "'%s' codec can't decode byte #x%02x: %s\n"  \
-                    "  in \"%s\", position %d"    \
-                    % (self.encoding, ord(self.character), self.reason,
-                            self.name, self.position)
-        else:
-            return "unacceptable character #x%04x: %s\n"    \
-                    "  in \"%s\", position %d"    \
-                    % (self.character, self.reason,
-                            self.name, self.position)
-
-class Reader(object):
-    # Reader:
-    # - determines the data encoding and converts it to a unicode string,
-    # - checks if characters are in allowed range,
-    # - adds '\0' to the end.
-
-    # Reader accepts
-    #  - a `bytes` object,
-    #  - a `str` object,
-    #  - a file-like object with its `read` method returning `str`,
-    #  - a file-like object with its `read` method returning `unicode`.
-
-    # Yeah, it's ugly and slow.
-
-    def __init__(self, stream):
-        self.name = None
-        self.stream = None
-        self.stream_pointer = 0
-        self.eof = True
-        self.buffer = ''
-        self.pointer = 0
-        self.raw_buffer = None
-        self.raw_decode = None
-        self.encoding = None
-        self.index = 0
-        self.line = 0
-        self.column = 0
-        if isinstance(stream, str):
-            self.name = "<unicode string>"
-            self.check_printable(stream)
-            self.buffer = stream+'\0'
-        elif isinstance(stream, bytes):
-            self.name = "<byte string>"
-            self.raw_buffer = stream
-            self.determine_encoding()
-        else:
-            self.stream = stream
-            self.name = getattr(stream, 'name', "<file>")
-            self.eof = False
-            self.raw_buffer = None
-            self.determine_encoding()
-
-    def peek(self, index=0):
-        try:
-            return self.buffer[self.pointer+index]
-        except IndexError:
-            self.update(index+1)
-            return self.buffer[self.pointer+index]
-
-    def prefix(self, length=1):
-        if self.pointer+length >= len(self.buffer):
-            self.update(length)
-        return self.buffer[self.pointer:self.pointer+length]
-
-    def forward(self, length=1):
-        if self.pointer+length+1 >= len(self.buffer):
-            self.update(length+1)
-        while length:
-            ch = self.buffer[self.pointer]
-            self.pointer += 1
-            self.index += 1
-            if ch in '\n\x85\u2028\u2029'  \
-                    or (ch == '\r' and self.buffer[self.pointer] != '\n'):
-                self.line += 1
-                self.column = 0
-            elif ch != '\uFEFF':
-                self.column += 1
-            length -= 1
-
-    def get_mark(self):
-        if self.stream is None:
-            return Mark(self.name, self.index, self.line, self.column,
-                    self.buffer, self.pointer)
-        else:
-            return Mark(self.name, self.index, self.line, self.column,
-                    None, None)
-
-    def determine_encoding(self):
-        while not self.eof and (self.raw_buffer is None or len(self.raw_buffer) < 2):
-            self.update_raw()
-        if isinstance(self.raw_buffer, bytes):
-            if self.raw_buffer.startswith(codecs.BOM_UTF16_LE):
-                self.raw_decode = codecs.utf_16_le_decode
-                self.encoding = 'utf-16-le'
-            elif self.raw_buffer.startswith(codecs.BOM_UTF16_BE):
-                self.raw_decode = codecs.utf_16_be_decode
-                self.encoding = 'utf-16-be'
-            else:
-                self.raw_decode = codecs.utf_8_decode
-                self.encoding = 'utf-8'
-        self.update(1)
-
-    NON_PRINTABLE = re.compile('[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\uD7FF\uE000-\uFFFD\U00010000-\U0010ffff]')
-    def check_printable(self, data):
-        match = self.NON_PRINTABLE.search(data)
-        if match:
-            character = match.group()
-            position = self.index+(len(self.buffer)-self.pointer)+match.start()
-            raise ReaderError(self.name, position, ord(character),
-                    'unicode', "special characters are not allowed")
-
-    def update(self, length):
-        if self.raw_buffer is None:
-            return
-        self.buffer = self.buffer[self.pointer:]
-        self.pointer = 0
-        while len(self.buffer) < length:
-            if not self.eof:
-                self.update_raw()
-            if self.raw_decode is not None:
-                try:
-                    data, converted = self.raw_decode(self.raw_buffer,
-                            'strict', self.eof)
-                except UnicodeDecodeError as exc:
-                    character = self.raw_buffer[exc.start]
-                    if self.stream is not None:
-                        position = self.stream_pointer-len(self.raw_buffer)+exc.start
-                    else:
-                        position = exc.start
-                    raise ReaderError(self.name, position, character,
-                            exc.encoding, exc.reason)
-            else:
-                data = self.raw_buffer
-                converted = len(data)
-            self.check_printable(data)
-            self.buffer += data
-            self.raw_buffer = self.raw_buffer[converted:]
-            if self.eof:
-                self.buffer += '\0'
-                self.raw_buffer = None
-                break
-
-    def update_raw(self, size=4096):
-        data = self.stream.read(size)
-        if self.raw_buffer is None:
-            self.raw_buffer = data
-        else:
-            self.raw_buffer += data
-        self.stream_pointer += len(data)
-        if not data:
-            self.eof = True
-
-#try:
-#    import psyco
-#    psyco.bind(Reader)
-#except ImportError:
-#    pass
diff --git a/lib3/yaml/representer.py b/lib3/yaml/representer.py
deleted file mode 100644
index 483005f..0000000
--- a/lib3/yaml/representer.py
+++ /dev/null
@@ -1,387 +0,0 @@
-
-__all__ = ['BaseRepresenter', 'SafeRepresenter', 'Representer',
-    'RepresenterError']
-
-from .error import *
-from .nodes import *
-
-import datetime, sys, copyreg, types, base64, collections
-
-class RepresenterError(YAMLError):
-    pass
-
-class BaseRepresenter:
-
-    yaml_representers = {}
-    yaml_multi_representers = {}
-
-    def __init__(self, default_style=None, default_flow_style=None):
-        self.default_style = default_style
-        self.default_flow_style = default_flow_style
-        self.represented_objects = {}
-        self.object_keeper = []
-        self.alias_key = None
-
-    def represent(self, data):
-        node = self.represent_data(data)
-        self.serialize(node)
-        self.represented_objects = {}
-        self.object_keeper = []
-        self.alias_key = None
-
-    def represent_data(self, data):
-        if self.ignore_aliases(data):
-            self.alias_key = None
-        else:
-            self.alias_key = id(data)
-        if self.alias_key is not None:
-            if self.alias_key in self.represented_objects:
-                node = self.represented_objects[self.alias_key]
-                #if node is None:
-                #    raise RepresenterError("recursive objects are not allowed: %r" % data)
-                return node
-            #self.represented_objects[alias_key] = None
-            self.object_keeper.append(data)
-        data_types = type(data).__mro__
-        if data_types[0] in self.yaml_representers:
-            node = self.yaml_representers[data_types[0]](self, data)
-        else:
-            for data_type in data_types:
-                if data_type in self.yaml_multi_representers:
-                    node = self.yaml_multi_representers[data_type](self, data)
-                    break
-            else:
-                if None in self.yaml_multi_representers:
-                    node = self.yaml_multi_representers[None](self, data)
-                elif None in self.yaml_representers:
-                    node = self.yaml_representers[None](self, data)
-                else:
-                    node = ScalarNode(None, str(data))
-        #if alias_key is not None:
-        #    self.represented_objects[alias_key] = node
-        return node
-
-    @classmethod
-    def add_representer(cls, data_type, representer):
-        if not 'yaml_representers' in cls.__dict__:
-            cls.yaml_representers = cls.yaml_representers.copy()
-        cls.yaml_representers[data_type] = representer
-
-    @classmethod
-    def add_multi_representer(cls, data_type, representer):
-        if not 'yaml_multi_representers' in cls.__dict__:
-            cls.yaml_multi_representers = cls.yaml_multi_representers.copy()
-        cls.yaml_multi_representers[data_type] = representer
-
-    def represent_scalar(self, tag, value, style=None):
-        if style is None:
-            style = self.default_style
-        node = ScalarNode(tag, value, style=style)
-        if self.alias_key is not None:
-            self.represented_objects[self.alias_key] = node
-        return node
-
-    def represent_sequence(self, tag, sequence, flow_style=None):
-        value = []
-        node = SequenceNode(tag, value, flow_style=flow_style)
-        if self.alias_key is not None:
-            self.represented_objects[self.alias_key] = node
-        best_style = True
-        for item in sequence:
-            node_item = self.represent_data(item)
-            if not (isinstance(node_item, ScalarNode) and not node_item.style):
-                best_style = False
-            value.append(node_item)
-        if flow_style is None:
-            if self.default_flow_style is not None:
-                node.flow_style = self.default_flow_style
-            else:
-                node.flow_style = best_style
-        return node
-
-    def represent_mapping(self, tag, mapping, flow_style=None):
-        value = []
-        node = MappingNode(tag, value, flow_style=flow_style)
-        if self.alias_key is not None:
-            self.represented_objects[self.alias_key] = node
-        best_style = True
-        if hasattr(mapping, 'items'):
-            mapping = list(mapping.items())
-            try:
-                mapping = sorted(mapping)
-            except TypeError:
-                pass
-        for item_key, item_value in mapping:
-            node_key = self.represent_data(item_key)
-            node_value = self.represent_data(item_value)
-            if not (isinstance(node_key, ScalarNode) and not node_key.style):
-                best_style = False
-            if not (isinstance(node_value, ScalarNode) and not node_value.style):
-                best_style = False
-            value.append((node_key, node_value))
-        if flow_style is None:
-            if self.default_flow_style is not None:
-                node.flow_style = self.default_flow_style
-            else:
-                node.flow_style = best_style
-        return node
-
-    def ignore_aliases(self, data):
-        return False
-
-class SafeRepresenter(BaseRepresenter):
-
-    def ignore_aliases(self, data):
-        if data is None:
-            return True
-        if isinstance(data, tuple) and data == ():
-            return True
-        if isinstance(data, (str, bytes, bool, int, float)):
-            return True
-
-    def represent_none(self, data):
-        return self.represent_scalar('tag:yaml.org,2002:null', 'null')
-
-    def represent_str(self, data):
-        return self.represent_scalar('tag:yaml.org,2002:str', data)
-
-    def represent_binary(self, data):
-        if hasattr(base64, 'encodebytes'):
-            data = base64.encodebytes(data).decode('ascii')
-        else:
-            data = base64.encodestring(data).decode('ascii')
-        return self.represent_scalar('tag:yaml.org,2002:binary', data, style='|')
-
-    def represent_bool(self, data):
-        if data:
-            value = 'true'
-        else:
-            value = 'false'
-        return self.represent_scalar('tag:yaml.org,2002:bool', value)
-
-    def represent_int(self, data):
-        return self.represent_scalar('tag:yaml.org,2002:int', str(data))
-
-    inf_value = 1e300
-    while repr(inf_value) != repr(inf_value*inf_value):
-        inf_value *= inf_value
-
-    def represent_float(self, data):
-        if data != data or (data == 0.0 and data == 1.0):
-            value = '.nan'
-        elif data == self.inf_value:
-            value = '.inf'
-        elif data == -self.inf_value:
-            value = '-.inf'
-        else:
-            value = repr(data).lower()
-            # Note that in some cases `repr(data)` represents a float number
-            # without the decimal parts.  For instance:
-            #   >>> repr(1e17)
-            #   '1e17'
-            # Unfortunately, this is not a valid float representation according
-            # to the definition of the `!!float` tag.  We fix this by adding
-            # '.0' before the 'e' symbol.
-            if '.' not in value and 'e' in value:
-                value = value.replace('e', '.0e', 1)
-        return self.represent_scalar('tag:yaml.org,2002:float', value)
-
-    def represent_list(self, data):
-        #pairs = (len(data) > 0 and isinstance(data, list))
-        #if pairs:
-        #    for item in data:
-        #        if not isinstance(item, tuple) or len(item) != 2:
-        #            pairs = False
-        #            break
-        #if not pairs:
-            return self.represent_sequence('tag:yaml.org,2002:seq', data)
-        #value = []
-        #for item_key, item_value in data:
-        #    value.append(self.represent_mapping(u'tag:yaml.org,2002:map',
-        #        [(item_key, item_value)]))
-        #return SequenceNode(u'tag:yaml.org,2002:pairs', value)
-
-    def represent_dict(self, data):
-        return self.represent_mapping('tag:yaml.org,2002:map', data)
-
-    def represent_set(self, data):
-        value = {}
-        for key in data:
-            value[key] = None
-        return self.represent_mapping('tag:yaml.org,2002:set', value)
-
-    def represent_date(self, data):
-        value = data.isoformat()
-        return self.represent_scalar('tag:yaml.org,2002:timestamp', value)
-
-    def represent_datetime(self, data):
-        value = data.isoformat(' ')
-        return self.represent_scalar('tag:yaml.org,2002:timestamp', value)
-
-    def represent_yaml_object(self, tag, data, cls, flow_style=None):
-        if hasattr(data, '__getstate__'):
-            state = data.__getstate__()
-        else:
-            state = data.__dict__.copy()
-        return self.represent_mapping(tag, state, flow_style=flow_style)
-
-    def represent_undefined(self, data):
-        raise RepresenterError("cannot represent an object", data)
-
-SafeRepresenter.add_representer(type(None),
-        SafeRepresenter.represent_none)
-
-SafeRepresenter.add_representer(str,
-        SafeRepresenter.represent_str)
-
-SafeRepresenter.add_representer(bytes,
-        SafeRepresenter.represent_binary)
-
-SafeRepresenter.add_representer(bool,
-        SafeRepresenter.represent_bool)
-
-SafeRepresenter.add_representer(int,
-        SafeRepresenter.represent_int)
-
-SafeRepresenter.add_representer(float,
-        SafeRepresenter.represent_float)
-
-SafeRepresenter.add_representer(list,
-        SafeRepresenter.represent_list)
-
-SafeRepresenter.add_representer(tuple,
-        SafeRepresenter.represent_list)
-
-SafeRepresenter.add_representer(dict,
-        SafeRepresenter.represent_dict)
-
-SafeRepresenter.add_representer(set,
-        SafeRepresenter.represent_set)
-
-SafeRepresenter.add_representer(datetime.date,
-        SafeRepresenter.represent_date)
-
-SafeRepresenter.add_representer(datetime.datetime,
-        SafeRepresenter.represent_datetime)
-
-SafeRepresenter.add_representer(None,
-        SafeRepresenter.represent_undefined)
-
-class Representer(SafeRepresenter):
-
-    def represent_complex(self, data):
-        if data.imag == 0.0:
-            data = '%r' % data.real
-        elif data.real == 0.0:
-            data = '%rj' % data.imag
-        elif data.imag > 0:
-            data = '%r+%rj' % (data.real, data.imag)
-        else:
-            data = '%r%rj' % (data.real, data.imag)
-        return self.represent_scalar('tag:yaml.org,2002:python/complex', data)
-
-    def represent_tuple(self, data):
-        return self.represent_sequence('tag:yaml.org,2002:python/tuple', data)
-
-    def represent_name(self, data):
-        name = '%s.%s' % (data.__module__, data.__name__)
-        return self.represent_scalar('tag:yaml.org,2002:python/name:'+name, '')
-
-    def represent_module(self, data):
-        return self.represent_scalar(
-                'tag:yaml.org,2002:python/module:'+data.__name__, '')
-
-    def represent_object(self, data):
-        # We use __reduce__ API to save the data. data.__reduce__ returns
-        # a tuple of length 2-5:
-        #   (function, args, state, listitems, dictitems)
-
-        # For reconstructing, we calls function(*args), then set its state,
-        # listitems, and dictitems if they are not None.
-
-        # A special case is when function.__name__ == '__newobj__'. In this
-        # case we create the object with args[0].__new__(*args).
-
-        # Another special case is when __reduce__ returns a string - we don't
-        # support it.
-
-        # We produce a !!python/object, !!python/object/new or
-        # !!python/object/apply node.
-
-        cls = type(data)
-        if cls in copyreg.dispatch_table:
-            reduce = copyreg.dispatch_table[cls](data)
-        elif hasattr(data, '__reduce_ex__'):
-            reduce = data.__reduce_ex__(2)
-        elif hasattr(data, '__reduce__'):
-            reduce = data.__reduce__()
-        else:
-            raise RepresenterError("cannot represent an object", data)
-        reduce = (list(reduce)+[None]*5)[:5]
-        function, args, state, listitems, dictitems = reduce
-        args = list(args)
-        if state is None:
-            state = {}
-        if listitems is not None:
-            listitems = list(listitems)
-        if dictitems is not None:
-            dictitems = dict(dictitems)
-        if function.__name__ == '__newobj__':
-            function = args[0]
-            args = args[1:]
-            tag = 'tag:yaml.org,2002:python/object/new:'
-            newobj = True
-        else:
-            tag = 'tag:yaml.org,2002:python/object/apply:'
-            newobj = False
-        function_name = '%s.%s' % (function.__module__, function.__name__)
-        if not args and not listitems and not dictitems \
-                and isinstance(state, dict) and newobj:
-            return self.represent_mapping(
-                    'tag:yaml.org,2002:python/object:'+function_name, state)
-        if not listitems and not dictitems  \
-                and isinstance(state, dict) and not state:
-            return self.represent_sequence(tag+function_name, args)
-        value = {}
-        if args:
-            value['args'] = args
-        if state or not isinstance(state, dict):
-            value['state'] = state
-        if listitems:
-            value['listitems'] = listitems
-        if dictitems:
-            value['dictitems'] = dictitems
-        return self.represent_mapping(tag+function_name, value)
-
-    def represent_ordered_dict(self, data):
-        # Provide uniform representation across different Python versions.
-        data_type = type(data)
-        tag = 'tag:yaml.org,2002:python/object/apply:%s.%s' \
-                % (data_type.__module__, data_type.__name__)
-        items = [[key, value] for key, value in data.items()]
-        return self.represent_sequence(tag, [items])
-
-Representer.add_representer(complex,
-        Representer.represent_complex)
-
-Representer.add_representer(tuple,
-        Representer.represent_tuple)
-
-Representer.add_representer(type,
-        Representer.represent_name)
-
-Representer.add_representer(collections.OrderedDict,
-        Representer.represent_ordered_dict)
-
-Representer.add_representer(types.FunctionType,
-        Representer.represent_name)
-
-Representer.add_representer(types.BuiltinFunctionType,
-        Representer.represent_name)
-
-Representer.add_representer(types.ModuleType,
-        Representer.represent_module)
-
-Representer.add_multi_representer(object,
-        Representer.represent_object)
-
diff --git a/lib3/yaml/resolver.py b/lib3/yaml/resolver.py
deleted file mode 100644
index 02b82e7..0000000
--- a/lib3/yaml/resolver.py
+++ /dev/null
@@ -1,227 +0,0 @@
-
-__all__ = ['BaseResolver', 'Resolver']
-
-from .error import *
-from .nodes import *
-
-import re
-
-class ResolverError(YAMLError):
-    pass
-
-class BaseResolver:
-
-    DEFAULT_SCALAR_TAG = 'tag:yaml.org,2002:str'
-    DEFAULT_SEQUENCE_TAG = 'tag:yaml.org,2002:seq'
-    DEFAULT_MAPPING_TAG = 'tag:yaml.org,2002:map'
-
-    yaml_implicit_resolvers = {}
-    yaml_path_resolvers = {}
-
-    def __init__(self):
-        self.resolver_exact_paths = []
-        self.resolver_prefix_paths = []
-
-    @classmethod
-    def add_implicit_resolver(cls, tag, regexp, first):
-        if not 'yaml_implicit_resolvers' in cls.__dict__:
-            implicit_resolvers = {}
-            for key in cls.yaml_implicit_resolvers:
-                implicit_resolvers[key] = cls.yaml_implicit_resolvers[key][:]
-            cls.yaml_implicit_resolvers = implicit_resolvers
-        if first is None:
-            first = [None]
-        for ch in first:
-            cls.yaml_implicit_resolvers.setdefault(ch, []).append((tag, regexp))
-
-    @classmethod
-    def add_path_resolver(cls, tag, path, kind=None):
-        # Note: `add_path_resolver` is experimental.  The API could be changed.
-        # `new_path` is a pattern that is matched against the path from the
-        # root to the node that is being considered.  `node_path` elements are
-        # tuples `(node_check, index_check)`.  `node_check` is a node class:
-        # `ScalarNode`, `SequenceNode`, `MappingNode` or `None`.  `None`
-        # matches any kind of a node.  `index_check` could be `None`, a boolean
-        # value, a string value, or a number.  `None` and `False` match against
-        # any _value_ of sequence and mapping nodes.  `True` matches against
-        # any _key_ of a mapping node.  A string `index_check` matches against
-        # a mapping value that corresponds to a scalar key which content is
-        # equal to the `index_check` value.  An integer `index_check` matches
-        # against a sequence value with the index equal to `index_check`.
-        if not 'yaml_path_resolvers' in cls.__dict__:
-            cls.yaml_path_resolvers = cls.yaml_path_resolvers.copy()
-        new_path = []
-        for element in path:
-            if isinstance(element, (list, tuple)):
-                if len(element) == 2:
-                    node_check, index_check = element
-                elif len(element) == 1:
-                    node_check = element[0]
-                    index_check = True
-                else:
-                    raise ResolverError("Invalid path element: %s" % element)
-            else:
-                node_check = None
-                index_check = element
-            if node_check is str:
-                node_check = ScalarNode
-            elif node_check is list:
-                node_check = SequenceNode
-            elif node_check is dict:
-                node_check = MappingNode
-            elif node_check not in [ScalarNode, SequenceNode, MappingNode]  \
-                    and not isinstance(node_check, str) \
-                    and node_check is not None:
-                raise ResolverError("Invalid node checker: %s" % node_check)
-            if not isinstance(index_check, (str, int))  \
-                    and index_check is not None:
-                raise ResolverError("Invalid index checker: %s" % index_check)
-            new_path.append((node_check, index_check))
-        if kind is str:
-            kind = ScalarNode
-        elif kind is list:
-            kind = SequenceNode
-        elif kind is dict:
-            kind = MappingNode
-        elif kind not in [ScalarNode, SequenceNode, MappingNode]    \
-                and kind is not None:
-            raise ResolverError("Invalid node kind: %s" % kind)
-        cls.yaml_path_resolvers[tuple(new_path), kind] = tag
-
-    def descend_resolver(self, current_node, current_index):
-        if not self.yaml_path_resolvers:
-            return
-        exact_paths = {}
-        prefix_paths = []
-        if current_node:
-            depth = len(self.resolver_prefix_paths)
-            for path, kind in self.resolver_prefix_paths[-1]:
-                if self.check_resolver_prefix(depth, path, kind,
-                        current_node, current_index):
-                    if len(path) > depth:
-                        prefix_paths.append((path, kind))
-                    else:
-                        exact_paths[kind] = self.yaml_path_resolvers[path, kind]
-        else:
-            for path, kind in self.yaml_path_resolvers:
-                if not path:
-                    exact_paths[kind] = self.yaml_path_resolvers[path, kind]
-                else:
-                    prefix_paths.append((path, kind))
-        self.resolver_exact_paths.append(exact_paths)
-        self.resolver_prefix_paths.append(prefix_paths)
-
-    def ascend_resolver(self):
-        if not self.yaml_path_resolvers:
-            return
-        self.resolver_exact_paths.pop()
-        self.resolver_prefix_paths.pop()
-
-    def check_resolver_prefix(self, depth, path, kind,
-            current_node, current_index):
-        node_check, index_check = path[depth-1]
-        if isinstance(node_check, str):
-            if current_node.tag != node_check:
-                return
-        elif node_check is not None:
-            if not isinstance(current_node, node_check):
-                return
-        if index_check is True and current_index is not None:
-            return
-        if (index_check is False or index_check is None)    \
-                and current_index is None:
-            return
-        if isinstance(index_check, str):
-            if not (isinstance(current_index, ScalarNode)
-                    and index_check == current_index.value):
-                return
-        elif isinstance(index_check, int) and not isinstance(index_check, bool):
-            if index_check != current_index:
-                return
-        return True
-
-    def resolve(self, kind, value, implicit):
-        if kind is ScalarNode and implicit[0]:
-            if value == '':
-                resolvers = self.yaml_implicit_resolvers.get('', [])
-            else:
-                resolvers = self.yaml_implicit_resolvers.get(value[0], [])
-            resolvers += self.yaml_implicit_resolvers.get(None, [])
-            for tag, regexp in resolvers:
-                if regexp.match(value):
-                    return tag
-            implicit = implicit[1]
-        if self.yaml_path_resolvers:
-            exact_paths = self.resolver_exact_paths[-1]
-            if kind in exact_paths:
-                return exact_paths[kind]
-            if None in exact_paths:
-                return exact_paths[None]
-        if kind is ScalarNode:
-            return self.DEFAULT_SCALAR_TAG
-        elif kind is SequenceNode:
-            return self.DEFAULT_SEQUENCE_TAG
-        elif kind is MappingNode:
-            return self.DEFAULT_MAPPING_TAG
-
-class Resolver(BaseResolver):
-    pass
-
-Resolver.add_implicit_resolver(
-        'tag:yaml.org,2002:bool',
-        re.compile(r'''^(?:yes|Yes|YES|no|No|NO
-                    |true|True|TRUE|false|False|FALSE
-                    |on|On|ON|off|Off|OFF)$''', re.X),
-        list('yYnNtTfFoO'))
-
-Resolver.add_implicit_resolver(
-        'tag:yaml.org,2002:float',
-        re.compile(r'''^(?:[-+]?(?:[0-9][0-9_]*)\.[0-9_]*(?:[eE][-+][0-9]+)?
-                    |\.[0-9_]+(?:[eE][-+][0-9]+)?
-                    |[-+]?[0-9][0-9_]*(?::[0-5]?[0-9])+\.[0-9_]*
-                    |[-+]?\.(?:inf|Inf|INF)
-                    |\.(?:nan|NaN|NAN))$''', re.X),
-        list('-+0123456789.'))
-
-Resolver.add_implicit_resolver(
-        'tag:yaml.org,2002:int',
-        re.compile(r'''^(?:[-+]?0b[0-1_]+
-                    |[-+]?0[0-7_]+
-                    |[-+]?(?:0|[1-9][0-9_]*)
-                    |[-+]?0x[0-9a-fA-F_]+
-                    |[-+]?[1-9][0-9_]*(?::[0-5]?[0-9])+)$''', re.X),
-        list('-+0123456789'))
-
-Resolver.add_implicit_resolver(
-        'tag:yaml.org,2002:merge',
-        re.compile(r'^(?:<<)$'),
-        ['<'])
-
-Resolver.add_implicit_resolver(
-        'tag:yaml.org,2002:null',
-        re.compile(r'''^(?: ~
-                    |null|Null|NULL
-                    | )$''', re.X),
-        ['~', 'n', 'N', ''])
-
-Resolver.add_implicit_resolver(
-        'tag:yaml.org,2002:timestamp',
-        re.compile(r'''^(?:[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]
-                    |[0-9][0-9][0-9][0-9] -[0-9][0-9]? -[0-9][0-9]?
-                     (?:[Tt]|[ \t]+)[0-9][0-9]?
-                     :[0-9][0-9] :[0-9][0-9] (?:\.[0-9]*)?
-                     (?:[ \t]*(?:Z|[-+][0-9][0-9]?(?::[0-9][0-9])?))?)$''', re.X),
-        list('0123456789'))
-
-Resolver.add_implicit_resolver(
-        'tag:yaml.org,2002:value',
-        re.compile(r'^(?:=)$'),
-        ['='])
-
-# The following resolver is only for documentation purposes. It cannot work
-# because plain scalars cannot start with '!', '&', or '*'.
-Resolver.add_implicit_resolver(
-        'tag:yaml.org,2002:yaml',
-        re.compile(r'^(?:!|&|\*)$'),
-        list('!&*'))
-
diff --git a/lib3/yaml/scanner.py b/lib3/yaml/scanner.py
deleted file mode 100644
index 3b49407..0000000
--- a/lib3/yaml/scanner.py
+++ /dev/null
@@ -1,1438 +0,0 @@
-
-# Scanner produces tokens of the following types:
-# STREAM-START
-# STREAM-END
-# DIRECTIVE(name, value)
-# DOCUMENT-START
-# DOCUMENT-END
-# BLOCK-SEQUENCE-START
-# BLOCK-MAPPING-START
-# BLOCK-END
-# FLOW-SEQUENCE-START
-# FLOW-MAPPING-START
-# FLOW-SEQUENCE-END
-# FLOW-MAPPING-END
-# BLOCK-ENTRY
-# FLOW-ENTRY
-# KEY
-# VALUE
-# ALIAS(value)
-# ANCHOR(value)
-# TAG(value)
-# SCALAR(value, plain, style)
-#
-# Read comments in the Scanner code for more details.
-#
-
-__all__ = ['Scanner', 'ScannerError']
-
-from .error import MarkedYAMLError
-from .tokens import *
-
-class ScannerError(MarkedYAMLError):
-    pass
-
-class SimpleKey:
-    # See below simple keys treatment.
-
-    def __init__(self, token_number, required, index, line, column, mark):
-        self.token_number = token_number
-        self.required = required
-        self.index = index
-        self.line = line
-        self.column = column
-        self.mark = mark
-
-class Scanner:
-
-    def __init__(self):
-        """Initialize the scanner."""
-        # It is assumed that Scanner and Reader will have a common descendant.
-        # Reader do the dirty work of checking for BOM and converting the
-        # input data to Unicode. It also adds NUL to the end.
-        #
-        # Reader supports the following methods
-        #   self.peek(i=0)       # peek the next i-th character
-        #   self.prefix(l=1)     # peek the next l characters
-        #   self.forward(l=1)    # read the next l characters and move the pointer.
-
-        # Had we reached the end of the stream?
-        self.done = False
-
-        # The number of unclosed '{' and '['. `flow_level == 0` means block
-        # context.
-        self.flow_level = 0
-
-        # List of processed tokens that are not yet emitted.
-        self.tokens = []
-
-        # Add the STREAM-START token.
-        self.fetch_stream_start()
-
-        # Number of tokens that were emitted through the `get_token` method.
-        self.tokens_taken = 0
-
-        # The current indentation level.
-        self.indent = -1
-
-        # Past indentation levels.
-        self.indents = []
-
-        # Variables related to simple keys treatment.
-
-        # A simple key is a key that is not denoted by the '?' indicator.
-        # Example of simple keys:
-        #   ---
-        #   block simple key: value
-        #   ? not a simple key:
-        #   : { flow simple key: value }
-        # We emit the KEY token before all keys, so when we find a potential
-        # simple key, we try to locate the corresponding ':' indicator.
-        # Simple keys should be limited to a single line and 1024 characters.
-
-        # Can a simple key start at the current position? A simple key may
-        # start:
-        # - at the beginning of the line, not counting indentation spaces
-        #       (in block context),
-        # - after '{', '[', ',' (in the flow context),
-        # - after '?', ':', '-' (in the block context).
-        # In the block context, this flag also signifies if a block collection
-        # may start at the current position.
-        self.allow_simple_key = True
-
-        # Keep track of possible simple keys. This is a dictionary. The key
-        # is `flow_level`; there can be no more that one possible simple key
-        # for each level. The value is a SimpleKey record:
-        #   (token_number, required, index, line, column, mark)
-        # A simple key may start with ALIAS, ANCHOR, TAG, SCALAR(flow),
-        # '[', or '{' tokens.
-        self.possible_simple_keys = {}
-
-    # Public methods.
-
-    def check_token(self, *choices):
-        # Check if the next token is one of the given types.
-        while self.need_more_tokens():
-            self.fetch_more_tokens()
-        if self.tokens:
-            if not choices:
-                return True
-            for choice in choices:
-                if isinstance(self.tokens[0], choice):
-                    return True
-        return False
-
-    def peek_token(self):
-        # Return the next token, but do not delete if from the queue.
-        while self.need_more_tokens():
-            self.fetch_more_tokens()
-        if self.tokens:
-            return self.tokens[0]
-
-    def get_token(self):
-        # Return the next token.
-        while self.need_more_tokens():
-            self.fetch_more_tokens()
-        if self.tokens:
-            self.tokens_taken += 1
-            return self.tokens.pop(0)
-
-    # Private methods.
-
-    def need_more_tokens(self):
-        if self.done:
-            return False
-        if not self.tokens:
-            return True
-        # The current token may be a potential simple key, so we
-        # need to look further.
-        self.stale_possible_simple_keys()
-        if self.next_possible_simple_key() == self.tokens_taken:
-            return True
-
-    def fetch_more_tokens(self):
-
-        # Eat whitespaces and comments until we reach the next token.
-        self.scan_to_next_token()
-
-        # Remove obsolete possible simple keys.
-        self.stale_possible_simple_keys()
-
-        # Compare the current indentation and column. It may add some tokens
-        # and decrease the current indentation level.
-        self.unwind_indent(self.column)
-
-        # Peek the next character.
-        ch = self.peek()
-
-        # Is it the end of stream?
-        if ch == '\0':
-            return self.fetch_stream_end()
-
-        # Is it a directive?
-        if ch == '%' and self.check_directive():
-            return self.fetch_directive()
-
-        # Is it the document start?
-        if ch == '-' and self.check_document_start():
-            return self.fetch_document_start()
-
-        # Is it the document end?
-        if ch == '.' and self.check_document_end():
-            return self.fetch_document_end()
-
-        # TODO: support for BOM within a stream.
-        #if ch == '\uFEFF':
-        #    return self.fetch_bom()    <-- issue BOMToken
-
-        # Note: the order of the following checks is NOT significant.
-
-        # Is it the flow sequence start indicator?
-        if ch == '[':
-            return self.fetch_flow_sequence_start()
-
-        # Is it the flow mapping start indicator?
-        if ch == '{':
-            return self.fetch_flow_mapping_start()
-
-        # Is it the flow sequence end indicator?
-        if ch == ']':
-            return self.fetch_flow_sequence_end()
-
-        # Is it the flow mapping end indicator?
-        if ch == '}':
-            return self.fetch_flow_mapping_end()
-
-        # Is it the flow entry indicator?
-        if ch == ',':
-            return self.fetch_flow_entry()
-
-        # Is it the block entry indicator?
-        if ch == '-' and self.check_block_entry():
-            return self.fetch_block_entry()
-
-        # Is it the key indicator?
-        if ch == '?' and self.check_key():
-            return self.fetch_key()
-
-        # Is it the value indicator?
-        if ch == ':' and self.check_value():
-            return self.fetch_value()
-
-        # Is it an alias?
-        if ch == '*':
-            return self.fetch_alias()
-
-        # Is it an anchor?
-        if ch == '&':
-            return self.fetch_anchor()
-
-        # Is it a tag?
-        if ch == '!':
-            return self.fetch_tag()
-
-        # Is it a literal scalar?
-        if ch == '|' and not self.flow_level:
-            return self.fetch_literal()
-
-        # Is it a folded scalar?
-        if ch == '>' and not self.flow_level:
-            return self.fetch_folded()
-
-        # Is it a single quoted scalar?
-        if ch == '\'':
-            return self.fetch_single()
-
-        # Is it a double quoted scalar?
-        if ch == '\"':
-            return self.fetch_double()
-
-        # It must be a plain scalar then.
-        if self.check_plain():
-            return self.fetch_plain()
-
-        # No? It's an error. Let's produce a nice error message.
-        raise ScannerError("while scanning for the next token", None,
-                "found character %r that cannot start any token" % ch,
-                self.get_mark())
-
-    # Simple keys treatment.
-
-    def next_possible_simple_key(self):
-        # Return the number of the nearest possible simple key. Actually we
-        # don't need to loop through the whole dictionary. We may replace it
-        # with the following code:
-        #   if not self.possible_simple_keys:
-        #       return None
-        #   return self.possible_simple_keys[
-        #           min(self.possible_simple_keys.keys())].token_number
-        min_token_number = None
-        for level in self.possible_simple_keys:
-            key = self.possible_simple_keys[level]
-            if min_token_number is None or key.token_number < min_token_number:
-                min_token_number = key.token_number
-        return min_token_number
-
-    def stale_possible_simple_keys(self):
-        # Remove entries that are no longer possible simple keys. According to
-        # the YAML specification, simple keys
-        # - should be limited to a single line,
-        # - should be no longer than 1024 characters.
-        # Disabling this procedure will allow simple keys of any length and
-        # height (may cause problems if indentation is broken though).
-        for level in list(self.possible_simple_keys):
-            key = self.possible_simple_keys[level]
-            if key.line != self.line  \
-                    or self.index-key.index > 1024:
-                if key.required:
-                    raise ScannerError("while scanning a simple key", key.mark,
-                            "could not find expected ':'", self.get_mark())
-                del self.possible_simple_keys[level]
-
-    def save_possible_simple_key(self):
-        # The next token may start a simple key. We check if it's possible
-        # and save its position. This function is called for
-        #   ALIAS, ANCHOR, TAG, SCALAR(flow), '[', and '{'.
-
-        # Check if a simple key is required at the current position.
-        required = not self.flow_level and self.indent == self.column
-
-        # The next token might be a simple key. Let's save it's number and
-        # position.
-        if self.allow_simple_key:
-            self.remove_possible_simple_key()
-            token_number = self.tokens_taken+len(self.tokens)
-            key = SimpleKey(token_number, required,
-                    self.index, self.line, self.column, self.get_mark())
-            self.possible_simple_keys[self.flow_level] = key
-
-    def remove_possible_simple_key(self):
-        # Remove the saved possible key position at the current flow level.
-        if self.flow_level in self.possible_simple_keys:
-            key = self.possible_simple_keys[self.flow_level]
-            
-            if key.required:
-                raise ScannerError("while scanning a simple key", key.mark,
-                        "could not find expected ':'", self.get_mark())
-
-            del self.possible_simple_keys[self.flow_level]
-
-    # Indentation functions.
-
-    def unwind_indent(self, column):
-
-        ## In flow context, tokens should respect indentation.
-        ## Actually the condition should be `self.indent >= column` according to
-        ## the spec. But this condition will prohibit intuitively correct
-        ## constructions such as
-        ## key : {
-        ## }
-        #if self.flow_level and self.indent > column:
-        #    raise ScannerError(None, None,
-        #            "invalid intendation or unclosed '[' or '{'",
-        #            self.get_mark())
-
-        # In the flow context, indentation is ignored. We make the scanner less
-        # restrictive then specification requires.
-        if self.flow_level:
-            return
-
-        # In block context, we may need to issue the BLOCK-END tokens.
-        while self.indent > column:
-            mark = self.get_mark()
-            self.indent = self.indents.pop()
-            self.tokens.append(BlockEndToken(mark, mark))
-
-    def add_indent(self, column):
-        # Check if we need to increase indentation.
-        if self.indent < column:
-            self.indents.append(self.indent)
-            self.indent = column
-            return True
-        return False
-
-    # Fetchers.
-
-    def fetch_stream_start(self):
-        # We always add STREAM-START as the first token and STREAM-END as the
-        # last token.
-
-        # Read the token.
-        mark = self.get_mark()
-        
-        # Add STREAM-START.
-        self.tokens.append(StreamStartToken(mark, mark,
-            encoding=self.encoding))
-        
-
-    def fetch_stream_end(self):
-
-        # Set the current intendation to -1.
-        self.unwind_indent(-1)
-
-        # Reset simple keys.
-        self.remove_possible_simple_key()
-        self.allow_simple_key = False
-        self.possible_simple_keys = {}
-
-        # Read the token.
-        mark = self.get_mark()
-        
-        # Add STREAM-END.
-        self.tokens.append(StreamEndToken(mark, mark))
-
-        # The steam is finished.
-        self.done = True
-
-    def fetch_directive(self):
-        
-        # Set the current intendation to -1.
-        self.unwind_indent(-1)
-
-        # Reset simple keys.
-        self.remove_possible_simple_key()
-        self.allow_simple_key = False
-
-        # Scan and add DIRECTIVE.
-        self.tokens.append(self.scan_directive())
-
-    def fetch_document_start(self):
-        self.fetch_document_indicator(DocumentStartToken)
-
-    def fetch_document_end(self):
-        self.fetch_document_indicator(DocumentEndToken)
-
-    def fetch_document_indicator(self, TokenClass):
-
-        # Set the current intendation to -1.
-        self.unwind_indent(-1)
-
-        # Reset simple keys. Note that there could not be a block collection
-        # after '---'.
-        self.remove_possible_simple_key()
-        self.allow_simple_key = False
-
-        # Add DOCUMENT-START or DOCUMENT-END.
-        start_mark = self.get_mark()
-        self.forward(3)
-        end_mark = self.get_mark()
-        self.tokens.append(TokenClass(start_mark, end_mark))
-
-    def fetch_flow_sequence_start(self):
-        self.fetch_flow_collection_start(FlowSequenceStartToken)
-
-    def fetch_flow_mapping_start(self):
-        self.fetch_flow_collection_start(FlowMappingStartToken)
-
-    def fetch_flow_collection_start(self, TokenClass):
-
-        # '[' and '{' may start a simple key.
-        self.save_possible_simple_key()
-
-        # Increase the flow level.
-        self.flow_level += 1
-
-        # Simple keys are allowed after '[' and '{'.
-        self.allow_simple_key = True
-
-        # Add FLOW-SEQUENCE-START or FLOW-MAPPING-START.
-        start_mark = self.get_mark()
-        self.forward()
-        end_mark = self.get_mark()
-        self.tokens.append(TokenClass(start_mark, end_mark))
-
-    def fetch_flow_sequence_end(self):
-        self.fetch_flow_collection_end(FlowSequenceEndToken)
-
-    def fetch_flow_mapping_end(self):
-        self.fetch_flow_collection_end(FlowMappingEndToken)
-
-    def fetch_flow_collection_end(self, TokenClass):
-
-        # Reset possible simple key on the current level.
-        self.remove_possible_simple_key()
-
-        # Decrease the flow level.
-        self.flow_level -= 1
-
-        # No simple keys after ']' or '}'.
-        self.allow_simple_key = False
-
-        # Add FLOW-SEQUENCE-END or FLOW-MAPPING-END.
-        start_mark = self.get_mark()
-        self.forward()
-        end_mark = self.get_mark()
-        self.tokens.append(TokenClass(start_mark, end_mark))
-
-    def fetch_flow_entry(self):
-
-        # Simple keys are allowed after ','.
-        self.allow_simple_key = True
-
-        # Reset possible simple key on the current level.
-        self.remove_possible_simple_key()
-
-        # Add FLOW-ENTRY.
-        start_mark = self.get_mark()
-        self.forward()
-        end_mark = self.get_mark()
-        self.tokens.append(FlowEntryToken(start_mark, end_mark))
-
-    def fetch_block_entry(self):
-
-        # Block context needs additional checks.
-        if not self.flow_level:
-
-            # Are we allowed to start a new entry?
-            if not self.allow_simple_key:
-                raise ScannerError(None, None,
-                        "sequence entries are not allowed here",
-                        self.get_mark())
-
-            # We may need to add BLOCK-SEQUENCE-START.
-            if self.add_indent(self.column):
-                mark = self.get_mark()
-                self.tokens.append(BlockSequenceStartToken(mark, mark))
-
-        # It's an error for the block entry to occur in the flow context,
-        # but we let the parser detect this.
-        else:
-            pass
-
-        # Simple keys are allowed after '-'.
-        self.allow_simple_key = True
-
-        # Reset possible simple key on the current level.
-        self.remove_possible_simple_key()
-
-        # Add BLOCK-ENTRY.
-        start_mark = self.get_mark()
-        self.forward()
-        end_mark = self.get_mark()
-        self.tokens.append(BlockEntryToken(start_mark, end_mark))
-
-    def fetch_key(self):
-        
-        # Block context needs additional checks.
-        if not self.flow_level:
-
-            # Are we allowed to start a key (not necessary a simple)?
-            if not self.allow_simple_key:
-                raise ScannerError(None, None,
-                        "mapping keys are not allowed here",
-                        self.get_mark())
-
-            # We may need to add BLOCK-MAPPING-START.
-            if self.add_indent(self.column):
-                mark = self.get_mark()
-                self.tokens.append(BlockMappingStartToken(mark, mark))
-
-        # Simple keys are allowed after '?' in the block context.
-        self.allow_simple_key = not self.flow_level
-
-        # Reset possible simple key on the current level.
-        self.remove_possible_simple_key()
-
-        # Add KEY.
-        start_mark = self.get_mark()
-        self.forward()
-        end_mark = self.get_mark()
-        self.tokens.append(KeyToken(start_mark, end_mark))
-
-    def fetch_value(self):
-
-        # Do we determine a simple key?
-        if self.flow_level in self.possible_simple_keys:
-
-            # Add KEY.
-            key = self.possible_simple_keys[self.flow_level]
-            del self.possible_simple_keys[self.flow_level]
-            self.tokens.insert(key.token_number-self.tokens_taken,
-                    KeyToken(key.mark, key.mark))
-
-            # If this key starts a new block mapping, we need to add
-            # BLOCK-MAPPING-START.
-            if not self.flow_level:
-                if self.add_indent(key.column):
-                    self.tokens.insert(key.token_number-self.tokens_taken,
-                            BlockMappingStartToken(key.mark, key.mark))
-
-            # There cannot be two simple keys one after another.
-            self.allow_simple_key = False
-
-        # It must be a part of a complex key.
-        else:
-            
-            # Block context needs additional checks.
-            # (Do we really need them? They will be caught by the parser
-            # anyway.)
-            if not self.flow_level:
-
-                # We are allowed to start a complex value if and only if
-                # we can start a simple key.
-                if not self.allow_simple_key:
-                    raise ScannerError(None, None,
-                            "mapping values are not allowed here",
-                            self.get_mark())
-
-            # If this value starts a new block mapping, we need to add
-            # BLOCK-MAPPING-START.  It will be detected as an error later by
-            # the parser.
-            if not self.flow_level:
-                if self.add_indent(self.column):
-                    mark = self.get_mark()
-                    self.tokens.append(BlockMappingStartToken(mark, mark))
-
-            # Simple keys are allowed after ':' in the block context.
-            self.allow_simple_key = not self.flow_level
-
-            # Reset possible simple key on the current level.
-            self.remove_possible_simple_key()
-
-        # Add VALUE.
-        start_mark = self.get_mark()
-        self.forward()
-        end_mark = self.get_mark()
-        self.tokens.append(ValueToken(start_mark, end_mark))
-
-    def fetch_alias(self):
-
-        # ALIAS could be a simple key.
-        self.save_possible_simple_key()
-
-        # No simple keys after ALIAS.
-        self.allow_simple_key = False
-
-        # Scan and add ALIAS.
-        self.tokens.append(self.scan_anchor(AliasToken))
-
-    def fetch_anchor(self):
-
-        # ANCHOR could start a simple key.
-        self.save_possible_simple_key()
-
-        # No simple keys after ANCHOR.
-        self.allow_simple_key = False
-
-        # Scan and add ANCHOR.
-        self.tokens.append(self.scan_anchor(AnchorToken))
-
-    def fetch_tag(self):
-
-        # TAG could start a simple key.
-        self.save_possible_simple_key()
-
-        # No simple keys after TAG.
-        self.allow_simple_key = False
-
-        # Scan and add TAG.
-        self.tokens.append(self.scan_tag())
-
-    def fetch_literal(self):
-        self.fetch_block_scalar(style='|')
-
-    def fetch_folded(self):
-        self.fetch_block_scalar(style='>')
-
-    def fetch_block_scalar(self, style):
-
-        # A simple key may follow a block scalar.
-        self.allow_simple_key = True
-
-        # Reset possible simple key on the current level.
-        self.remove_possible_simple_key()
-
-        # Scan and add SCALAR.
-        self.tokens.append(self.scan_block_scalar(style))
-
-    def fetch_single(self):
-        self.fetch_flow_scalar(style='\'')
-
-    def fetch_double(self):
-        self.fetch_flow_scalar(style='"')
-
-    def fetch_flow_scalar(self, style):
-
-        # A flow scalar could be a simple key.
-        self.save_possible_simple_key()
-
-        # No simple keys after flow scalars.
-        self.allow_simple_key = False
-
-        # Scan and add SCALAR.
-        self.tokens.append(self.scan_flow_scalar(style))
-
-    def fetch_plain(self):
-
-        # A plain scalar could be a simple key.
-        self.save_possible_simple_key()
-
-        # No simple keys after plain scalars. But note that `scan_plain` will
-        # change this flag if the scan is finished at the beginning of the
-        # line.
-        self.allow_simple_key = False
-
-        # Scan and add SCALAR. May change `allow_simple_key`.
-        self.tokens.append(self.scan_plain())
-
-    # Checkers.
-
-    def check_directive(self):
-
-        # DIRECTIVE:        ^ '%' ...
-        # The '%' indicator is already checked.
-        if self.column == 0:
-            return True
-
-    def check_document_start(self):
-
-        # DOCUMENT-START:   ^ '---' (' '|'\n')
-        if self.column == 0:
-            if self.prefix(3) == '---'  \
-                    and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
-                return True
-
-    def check_document_end(self):
-
-        # DOCUMENT-END:     ^ '...' (' '|'\n')
-        if self.column == 0:
-            if self.prefix(3) == '...'  \
-                    and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
-                return True
-
-    def check_block_entry(self):
-
-        # BLOCK-ENTRY:      '-' (' '|'\n')
-        return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
-
-    def check_key(self):
-
-        # KEY(flow context):    '?'
-        if self.flow_level:
-            return True
-
-        # KEY(block context):   '?' (' '|'\n')
-        else:
-            return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
-
-    def check_value(self):
-
-        # VALUE(flow context):  ':'
-        if self.flow_level:
-            return True
-
-        # VALUE(block context): ':' (' '|'\n')
-        else:
-            return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
-
-    def check_plain(self):
-
-        # A plain scalar may start with any non-space character except:
-        #   '-', '?', ':', ',', '[', ']', '{', '}',
-        #   '#', '&', '*', '!', '|', '>', '\'', '\"',
-        #   '%', '@', '`'.
-        #
-        # It may also start with
-        #   '-', '?', ':'
-        # if it is followed by a non-space character.
-        #
-        # Note that we limit the last rule to the block context (except the
-        # '-' character) because we want the flow context to be space
-        # independent.
-        ch = self.peek()
-        return ch not in '\0 \t\r\n\x85\u2028\u2029-?:,[]{}#&*!|>\'\"%@`'  \
-                or (self.peek(1) not in '\0 \t\r\n\x85\u2028\u2029'
-                        and (ch == '-' or (not self.flow_level and ch in '?:')))
-
-    # Scanners.
-
-    def scan_to_next_token(self):
-        # We ignore spaces, line breaks and comments.
-        # If we find a line break in the block context, we set the flag
-        # `allow_simple_key` on.
-        # The byte order mark is stripped if it's the first character in the
-        # stream. We do not yet support BOM inside the stream as the
-        # specification requires. Any such mark will be considered as a part
-        # of the document.
-        #
-        # TODO: We need to make tab handling rules more sane. A good rule is
-        #   Tabs cannot precede tokens
-        #   BLOCK-SEQUENCE-START, BLOCK-MAPPING-START, BLOCK-END,
-        #   KEY(block), VALUE(block), BLOCK-ENTRY
-        # So the checking code is
-        #   if <TAB>:
-        #       self.allow_simple_keys = False
-        # We also need to add the check for `allow_simple_keys == True` to
-        # `unwind_indent` before issuing BLOCK-END.
-        # Scanners for block, flow, and plain scalars need to be modified.
-
-        if self.index == 0 and self.peek() == '\uFEFF':
-            self.forward()
-        found = False
-        while not found:
-            while self.peek() == ' ':
-                self.forward()
-            if self.peek() == '#':
-                while self.peek() not in '\0\r\n\x85\u2028\u2029':
-                    self.forward()
-            if self.scan_line_break():
-                if not self.flow_level:
-                    self.allow_simple_key = True
-            else:
-                found = True
-
-    def scan_directive(self):
-        # See the specification for details.
-        start_mark = self.get_mark()
-        self.forward()
-        name = self.scan_directive_name(start_mark)
-        value = None
-        if name == 'YAML':
-            value = self.scan_yaml_directive_value(start_mark)
-            end_mark = self.get_mark()
-        elif name == 'TAG':
-            value = self.scan_tag_directive_value(start_mark)
-            end_mark = self.get_mark()
-        else:
-            end_mark = self.get_mark()
-            while self.peek() not in '\0\r\n\x85\u2028\u2029':
-                self.forward()
-        self.scan_directive_ignored_line(start_mark)
-        return DirectiveToken(name, value, start_mark, end_mark)
-
-    def scan_directive_name(self, start_mark):
-        # See the specification for details.
-        length = 0
-        ch = self.peek(length)
-        while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'  \
-                or ch in '-_':
-            length += 1
-            ch = self.peek(length)
-        if not length:
-            raise ScannerError("while scanning a directive", start_mark,
-                    "expected alphabetic or numeric character, but found %r"
-                    % ch, self.get_mark())
-        value = self.prefix(length)
-        self.forward(length)
-        ch = self.peek()
-        if ch not in '\0 \r\n\x85\u2028\u2029':
-            raise ScannerError("while scanning a directive", start_mark,
-                    "expected alphabetic or numeric character, but found %r"
-                    % ch, self.get_mark())
-        return value
-
-    def scan_yaml_directive_value(self, start_mark):
-        # See the specification for details.
-        while self.peek() == ' ':
-            self.forward()
-        major = self.scan_yaml_directive_number(start_mark)
-        if self.peek() != '.':
-            raise ScannerError("while scanning a directive", start_mark,
-                    "expected a digit or '.', but found %r" % self.peek(),
-                    self.get_mark())
-        self.forward()
-        minor = self.scan_yaml_directive_number(start_mark)
-        if self.peek() not in '\0 \r\n\x85\u2028\u2029':
-            raise ScannerError("while scanning a directive", start_mark,
-                    "expected a digit or ' ', but found %r" % self.peek(),
-                    self.get_mark())
-        return (major, minor)
-
-    def scan_yaml_directive_number(self, start_mark):
-        # See the specification for details.
-        ch = self.peek()
-        if not ('0' <= ch <= '9'):
-            raise ScannerError("while scanning a directive", start_mark,
-                    "expected a digit, but found %r" % ch, self.get_mark())
-        length = 0
-        while '0' <= self.peek(length) <= '9':
-            length += 1
-        value = int(self.prefix(length))
-        self.forward(length)
-        return value
-
-    def scan_tag_directive_value(self, start_mark):
-        # See the specification for details.
-        while self.peek() == ' ':
-            self.forward()
-        handle = self.scan_tag_directive_handle(start_mark)
-        while self.peek() == ' ':
-            self.forward()
-        prefix = self.scan_tag_directive_prefix(start_mark)
-        return (handle, prefix)
-
-    def scan_tag_directive_handle(self, start_mark):
-        # See the specification for details.
-        value = self.scan_tag_handle('directive', start_mark)
-        ch = self.peek()
-        if ch != ' ':
-            raise ScannerError("while scanning a directive", start_mark,
-                    "expected ' ', but found %r" % ch, self.get_mark())
-        return value
-
-    def scan_tag_directive_prefix(self, start_mark):
-        # See the specification for details.
-        value = self.scan_tag_uri('directive', start_mark)
-        ch = self.peek()
-        if ch not in '\0 \r\n\x85\u2028\u2029':
-            raise ScannerError("while scanning a directive", start_mark,
-                    "expected ' ', but found %r" % ch, self.get_mark())
-        return value
-
-    def scan_directive_ignored_line(self, start_mark):
-        # See the specification for details.
-        while self.peek() == ' ':
-            self.forward()
-        if self.peek() == '#':
-            while self.peek() not in '\0\r\n\x85\u2028\u2029':
-                self.forward()
-        ch = self.peek()
-        if ch not in '\0\r\n\x85\u2028\u2029':
-            raise ScannerError("while scanning a directive", start_mark,
-                    "expected a comment or a line break, but found %r"
-                        % ch, self.get_mark())
-        self.scan_line_break()
-
-    def scan_anchor(self, TokenClass):
-        # The specification does not restrict characters for anchors and
-        # aliases. This may lead to problems, for instance, the document:
-        #   [ *alias, value ]
-        # can be interpreted in two ways, as
-        #   [ "value" ]
-        # and
-        #   [ *alias , "value" ]
-        # Therefore we restrict aliases to numbers and ASCII letters.
-        start_mark = self.get_mark()
-        indicator = self.peek()
-        if indicator == '*':
-            name = 'alias'
-        else:
-            name = 'anchor'
-        self.forward()
-        length = 0
-        ch = self.peek(length)
-        while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'  \
-                or ch in '-_':
-            length += 1
-            ch = self.peek(length)
-        if not length:
-            raise ScannerError("while scanning an %s" % name, start_mark,
-                    "expected alphabetic or numeric character, but found %r"
-                    % ch, self.get_mark())
-        value = self.prefix(length)
-        self.forward(length)
-        ch = self.peek()
-        if ch not in '\0 \t\r\n\x85\u2028\u2029?:,]}%@`':
-            raise ScannerError("while scanning an %s" % name, start_mark,
-                    "expected alphabetic or numeric character, but found %r"
-                    % ch, self.get_mark())
-        end_mark = self.get_mark()
-        return TokenClass(value, start_mark, end_mark)
-
-    def scan_tag(self):
-        # See the specification for details.
-        start_mark = self.get_mark()
-        ch = self.peek(1)
-        if ch == '<':
-            handle = None
-            self.forward(2)
-            suffix = self.scan_tag_uri('tag', start_mark)
-            if self.peek() != '>':
-                raise ScannerError("while parsing a tag", start_mark,
-                        "expected '>', but found %r" % self.peek(),
-                        self.get_mark())
-            self.forward()
-        elif ch in '\0 \t\r\n\x85\u2028\u2029':
-            handle = None
-            suffix = '!'
-            self.forward()
-        else:
-            length = 1
-            use_handle = False
-            while ch not in '\0 \r\n\x85\u2028\u2029':
-                if ch == '!':
-                    use_handle = True
-                    break
-                length += 1
-                ch = self.peek(length)
-            handle = '!'
-            if use_handle:
-                handle = self.scan_tag_handle('tag', start_mark)
-            else:
-                handle = '!'
-                self.forward()
-            suffix = self.scan_tag_uri('tag', start_mark)
-        ch = self.peek()
-        if ch not in '\0 \r\n\x85\u2028\u2029':
-            raise ScannerError("while scanning a tag", start_mark,
-                    "expected ' ', but found %r" % ch, self.get_mark())
-        value = (handle, suffix)
-        end_mark = self.get_mark()
-        return TagToken(value, start_mark, end_mark)
-
-    def scan_block_scalar(self, style):
-        # See the specification for details.
-
-        if style == '>':
-            folded = True
-        else:
-            folded = False
-
-        chunks = []
-        start_mark = self.get_mark()
-
-        # Scan the header.
-        self.forward()
-        chomping, increment = self.scan_block_scalar_indicators(start_mark)
-        self.scan_block_scalar_ignored_line(start_mark)
-
-        # Determine the indentation level and go to the first non-empty line.
-        min_indent = self.indent+1
-        if min_indent < 1:
-            min_indent = 1
-        if increment is None:
-            breaks, max_indent, end_mark = self.scan_block_scalar_indentation()
-            indent = max(min_indent, max_indent)
-        else:
-            indent = min_indent+increment-1
-            breaks, end_mark = self.scan_block_scalar_breaks(indent)
-        line_break = ''
-
-        # Scan the inner part of the block scalar.
-        while self.column == indent and self.peek() != '\0':
-            chunks.extend(breaks)
-            leading_non_space = self.peek() not in ' \t'
-            length = 0
-            while self.peek(length) not in '\0\r\n\x85\u2028\u2029':
-                length += 1
-            chunks.append(self.prefix(length))
-            self.forward(length)
-            line_break = self.scan_line_break()
-            breaks, end_mark = self.scan_block_scalar_breaks(indent)
-            if self.column == indent and self.peek() != '\0':
-
-                # Unfortunately, folding rules are ambiguous.
-                #
-                # This is the folding according to the specification:
-                
-                if folded and line_break == '\n'    \
-                        and leading_non_space and self.peek() not in ' \t':
-                    if not breaks:
-                        chunks.append(' ')
-                else:
-                    chunks.append(line_break)
-                
-                # This is Clark Evans's interpretation (also in the spec
-                # examples):
-                #
-                #if folded and line_break == '\n':
-                #    if not breaks:
-                #        if self.peek() not in ' \t':
-                #            chunks.append(' ')
-                #        else:
-                #            chunks.append(line_break)
-                #else:
-                #    chunks.append(line_break)
-            else:
-                break
-
-        # Chomp the tail.
-        if chomping is not False:
-            chunks.append(line_break)
-        if chomping is True:
-            chunks.extend(breaks)
-
-        # We are done.
-        return ScalarToken(''.join(chunks), False, start_mark, end_mark,
-                style)
-
-    def scan_block_scalar_indicators(self, start_mark):
-        # See the specification for details.
-        chomping = None
-        increment = None
-        ch = self.peek()
-        if ch in '+-':
-            if ch == '+':
-                chomping = True
-            else:
-                chomping = False
-            self.forward()
-            ch = self.peek()
-            if ch in '0123456789':
-                increment = int(ch)
-                if increment == 0:
-                    raise ScannerError("while scanning a block scalar", start_mark,
-                            "expected indentation indicator in the range 1-9, but found 0",
-                            self.get_mark())
-                self.forward()
-        elif ch in '0123456789':
-            increment = int(ch)
-            if increment == 0:
-                raise ScannerError("while scanning a block scalar", start_mark,
-                        "expected indentation indicator in the range 1-9, but found 0",
-                        self.get_mark())
-            self.forward()
-            ch = self.peek()
-            if ch in '+-':
-                if ch == '+':
-                    chomping = True
-                else:
-                    chomping = False
-                self.forward()
-        ch = self.peek()
-        if ch not in '\0 \r\n\x85\u2028\u2029':
-            raise ScannerError("while scanning a block scalar", start_mark,
-                    "expected chomping or indentation indicators, but found %r"
-                    % ch, self.get_mark())
-        return chomping, increment
-
-    def scan_block_scalar_ignored_line(self, start_mark):
-        # See the specification for details.
-        while self.peek() == ' ':
-            self.forward()
-        if self.peek() == '#':
-            while self.peek() not in '\0\r\n\x85\u2028\u2029':
-                self.forward()
-        ch = self.peek()
-        if ch not in '\0\r\n\x85\u2028\u2029':
-            raise ScannerError("while scanning a block scalar", start_mark,
-                    "expected a comment or a line break, but found %r" % ch,
-                    self.get_mark())
-        self.scan_line_break()
-
-    def scan_block_scalar_indentation(self):
-        # See the specification for details.
-        chunks = []
-        max_indent = 0
-        end_mark = self.get_mark()
-        while self.peek() in ' \r\n\x85\u2028\u2029':
-            if self.peek() != ' ':
-                chunks.append(self.scan_line_break())
-                end_mark = self.get_mark()
-            else:
-                self.forward()
-                if self.column > max_indent:
-                    max_indent = self.column
-        return chunks, max_indent, end_mark
-
-    def scan_block_scalar_breaks(self, indent):
-        # See the specification for details.
-        chunks = []
-        end_mark = self.get_mark()
-        while self.column < indent and self.peek() == ' ':
-            self.forward()
-        while self.peek() in '\r\n\x85\u2028\u2029':
-            chunks.append(self.scan_line_break())
-            end_mark = self.get_mark()
-            while self.column < indent and self.peek() == ' ':
-                self.forward()
-        return chunks, end_mark
-
-    def scan_flow_scalar(self, style):
-        # See the specification for details.
-        # Note that we loose indentation rules for quoted scalars. Quoted
-        # scalars don't need to adhere indentation because " and ' clearly
-        # mark the beginning and the end of them. Therefore we are less
-        # restrictive then the specification requires. We only need to check
-        # that document separators are not included in scalars.
-        if style == '"':
-            double = True
-        else:
-            double = False
-        chunks = []
-        start_mark = self.get_mark()
-        quote = self.peek()
-        self.forward()
-        chunks.extend(self.scan_flow_scalar_non_spaces(double, start_mark))
-        while self.peek() != quote:
-            chunks.extend(self.scan_flow_scalar_spaces(double, start_mark))
-            chunks.extend(self.scan_flow_scalar_non_spaces(double, start_mark))
-        self.forward()
-        end_mark = self.get_mark()
-        return ScalarToken(''.join(chunks), False, start_mark, end_mark,
-                style)
-
-    ESCAPE_REPLACEMENTS = {
-        '0':    '\0',
-        'a':    '\x07',
-        'b':    '\x08',
-        't':    '\x09',
-        '\t':   '\x09',
-        'n':    '\x0A',
-        'v':    '\x0B',
-        'f':    '\x0C',
-        'r':    '\x0D',
-        'e':    '\x1B',
-        ' ':    '\x20',
-        '\"':   '\"',
-        '\\':   '\\',
-        'N':    '\x85',
-        '_':    '\xA0',
-        'L':    '\u2028',
-        'P':    '\u2029',
-    }
-
-    ESCAPE_CODES = {
-        'x':    2,
-        'u':    4,
-        'U':    8,
-    }
-
-    def scan_flow_scalar_non_spaces(self, double, start_mark):
-        # See the specification for details.
-        chunks = []
-        while True:
-            length = 0
-            while self.peek(length) not in '\'\"\\\0 \t\r\n\x85\u2028\u2029':
-                length += 1
-            if length:
-                chunks.append(self.prefix(length))
-                self.forward(length)
-            ch = self.peek()
-            if not double and ch == '\'' and self.peek(1) == '\'':
-                chunks.append('\'')
-                self.forward(2)
-            elif (double and ch == '\'') or (not double and ch in '\"\\'):
-                chunks.append(ch)
-                self.forward()
-            elif double and ch == '\\':
-                self.forward()
-                ch = self.peek()
-                if ch in self.ESCAPE_REPLACEMENTS:
-                    chunks.append(self.ESCAPE_REPLACEMENTS[ch])
-                    self.forward()
-                elif ch in self.ESCAPE_CODES:
-                    length = self.ESCAPE_CODES[ch]
-                    self.forward()
-                    for k in range(length):
-                        if self.peek(k) not in '0123456789ABCDEFabcdef':
-                            raise ScannerError("while scanning a double-quoted scalar", start_mark,
-                                    "expected escape sequence of %d hexdecimal numbers, but found %r" %
-                                        (length, self.peek(k)), self.get_mark())
-                    code = int(self.prefix(length), 16)
-                    chunks.append(chr(code))
-                    self.forward(length)
-                elif ch in '\r\n\x85\u2028\u2029':
-                    self.scan_line_break()
-                    chunks.extend(self.scan_flow_scalar_breaks(double, start_mark))
-                else:
-                    raise ScannerError("while scanning a double-quoted scalar", start_mark,
-                            "found unknown escape character %r" % ch, self.get_mark())
-            else:
-                return chunks
-
-    def scan_flow_scalar_spaces(self, double, start_mark):
-        # See the specification for details.
-        chunks = []
-        length = 0
-        while self.peek(length) in ' \t':
-            length += 1
-        whitespaces = self.prefix(length)
-        self.forward(length)
-        ch = self.peek()
-        if ch == '\0':
-            raise ScannerError("while scanning a quoted scalar", start_mark,
-                    "found unexpected end of stream", self.get_mark())
-        elif ch in '\r\n\x85\u2028\u2029':
-            line_break = self.scan_line_break()
-            breaks = self.scan_flow_scalar_breaks(double, start_mark)
-            if line_break != '\n':
-                chunks.append(line_break)
-            elif not breaks:
-                chunks.append(' ')
-            chunks.extend(breaks)
-        else:
-            chunks.append(whitespaces)
-        return chunks
-
-    def scan_flow_scalar_breaks(self, double, start_mark):
-        # See the specification for details.
-        chunks = []
-        while True:
-            # Instead of checking indentation, we check for document
-            # separators.
-            prefix = self.prefix(3)
-            if (prefix == '---' or prefix == '...')   \
-                    and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
-                raise ScannerError("while scanning a quoted scalar", start_mark,
-                        "found unexpected document separator", self.get_mark())
-            while self.peek() in ' \t':
-                self.forward()
-            if self.peek() in '\r\n\x85\u2028\u2029':
-                chunks.append(self.scan_line_break())
-            else:
-                return chunks
-
-    def scan_plain(self):
-        # See the specification for details.
-        # We add an additional restriction for the flow context:
-        #   plain scalars in the flow context cannot contain ',' or '?'.
-        # We also keep track of the `allow_simple_key` flag here.
-        # Indentation rules are loosed for the flow context.
-        chunks = []
-        start_mark = self.get_mark()
-        end_mark = start_mark
-        indent = self.indent+1
-        # We allow zero indentation for scalars, but then we need to check for
-        # document separators at the beginning of the line.
-        #if indent == 0:
-        #    indent = 1
-        spaces = []
-        while True:
-            length = 0
-            if self.peek() == '#':
-                break
-            while True:
-                ch = self.peek(length)
-                if ch in '\0 \t\r\n\x85\u2028\u2029'    \
-                        or (ch == ':' and
-                                self.peek(length+1) in '\0 \t\r\n\x85\u2028\u2029'
-                                      + (u',[]{}' if self.flow_level else u''))\
-                        or (self.flow_level and ch in ',?[]{}'):
-                    break
-                length += 1
-            if length == 0:
-                break
-            self.allow_simple_key = False
-            chunks.extend(spaces)
-            chunks.append(self.prefix(length))
-            self.forward(length)
-            end_mark = self.get_mark()
-            spaces = self.scan_plain_spaces(indent, start_mark)
-            if not spaces or self.peek() == '#' \
-                    or (not self.flow_level and self.column < indent):
-                break
-        return ScalarToken(''.join(chunks), True, start_mark, end_mark)
-
-    def scan_plain_spaces(self, indent, start_mark):
-        # See the specification for details.
-        # The specification is really confusing about tabs in plain scalars.
-        # We just forbid them completely. Do not use tabs in YAML!
-        chunks = []
-        length = 0
-        while self.peek(length) in ' ':
-            length += 1
-        whitespaces = self.prefix(length)
-        self.forward(length)
-        ch = self.peek()
-        if ch in '\r\n\x85\u2028\u2029':
-            line_break = self.scan_line_break()
-            self.allow_simple_key = True
-            prefix = self.prefix(3)
-            if (prefix == '---' or prefix == '...')   \
-                    and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
-                return
-            breaks = []
-            while self.peek() in ' \r\n\x85\u2028\u2029':
-                if self.peek() == ' ':
-                    self.forward()
-                else:
-                    breaks.append(self.scan_line_break())
-                    prefix = self.prefix(3)
-                    if (prefix == '---' or prefix == '...')   \
-                            and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029':
-                        return
-            if line_break != '\n':
-                chunks.append(line_break)
-            elif not breaks:
-                chunks.append(' ')
-            chunks.extend(breaks)
-        elif whitespaces:
-            chunks.append(whitespaces)
-        return chunks
-
-    def scan_tag_handle(self, name, start_mark):
-        # See the specification for details.
-        # For some strange reasons, the specification does not allow '_' in
-        # tag handles. I have allowed it anyway.
-        ch = self.peek()
-        if ch != '!':
-            raise ScannerError("while scanning a %s" % name, start_mark,
-                    "expected '!', but found %r" % ch, self.get_mark())
-        length = 1
-        ch = self.peek(length)
-        if ch != ' ':
-            while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'  \
-                    or ch in '-_':
-                length += 1
-                ch = self.peek(length)
-            if ch != '!':
-                self.forward(length)
-                raise ScannerError("while scanning a %s" % name, start_mark,
-                        "expected '!', but found %r" % ch, self.get_mark())
-            length += 1
-        value = self.prefix(length)
-        self.forward(length)
-        return value
-
-    def scan_tag_uri(self, name, start_mark):
-        # See the specification for details.
-        # Note: we do not check if URI is well-formed.
-        chunks = []
-        length = 0
-        ch = self.peek(length)
-        while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z'  \
-                or ch in '-;/?:@&=+$,_.!~*\'()[]%':
-            if ch == '%':
-                chunks.append(self.prefix(length))
-                self.forward(length)
-                length = 0
-                chunks.append(self.scan_uri_escapes(name, start_mark))
-            else:
-                length += 1
-            ch = self.peek(length)
-        if length:
-            chunks.append(self.prefix(length))
-            self.forward(length)
-            length = 0
-        if not chunks:
-            raise ScannerError("while parsing a %s" % name, start_mark,
-                    "expected URI, but found %r" % ch, self.get_mark())
-        return ''.join(chunks)
-
-    def scan_uri_escapes(self, name, start_mark):
-        # See the specification for details.
-        codes = []
-        mark = self.get_mark()
-        while self.peek() == '%':
-            self.forward()
-            for k in range(2):
-                if self.peek(k) not in '0123456789ABCDEFabcdef':
-                    raise ScannerError("while scanning a %s" % name, start_mark,
-                            "expected URI escape sequence of 2 hexdecimal numbers, but found %r"
-                            % self.peek(k), self.get_mark())
-            codes.append(int(self.prefix(2), 16))
-            self.forward(2)
-        try:
-            value = bytes(codes).decode('utf-8')
-        except UnicodeDecodeError as exc:
-            raise ScannerError("while scanning a %s" % name, start_mark, str(exc), mark)
-        return value
-
-    def scan_line_break(self):
-        # Transforms:
-        #   '\r\n'      :   '\n'
-        #   '\r'        :   '\n'
-        #   '\n'        :   '\n'
-        #   '\x85'      :   '\n'
-        #   '\u2028'    :   '\u2028'
-        #   '\u2029     :   '\u2029'
-        #   default     :   ''
-        ch = self.peek()
-        if ch in '\r\n\x85':
-            if self.prefix(2) == '\r\n':
-                self.forward(2)
-            else:
-                self.forward()
-            return '\n'
-        elif ch in '\u2028\u2029':
-            self.forward()
-            return ch
-        return ''
-
-#try:
-#    import psyco
-#    psyco.bind(Scanner)
-#except ImportError:
-#    pass
-
diff --git a/lib3/yaml/serializer.py b/lib3/yaml/serializer.py
deleted file mode 100644
index fe911e6..0000000
--- a/lib3/yaml/serializer.py
+++ /dev/null
@@ -1,111 +0,0 @@
-
-__all__ = ['Serializer', 'SerializerError']
-
-from .error import YAMLError
-from .events import *
-from .nodes import *
-
-class SerializerError(YAMLError):
-    pass
-
-class Serializer:
-
-    ANCHOR_TEMPLATE = 'id%03d'
-
-    def __init__(self, encoding=None,
-            explicit_start=None, explicit_end=None, version=None, tags=None):
-        self.use_encoding = encoding
-        self.use_explicit_start = explicit_start
-        self.use_explicit_end = explicit_end
-        self.use_version = version
-        self.use_tags = tags
-        self.serialized_nodes = {}
-        self.anchors = {}
-        self.last_anchor_id = 0
-        self.closed = None
-
-    def open(self):
-        if self.closed is None:
-            self.emit(StreamStartEvent(encoding=self.use_encoding))
-            self.closed = False
-        elif self.closed:
-            raise SerializerError("serializer is closed")
-        else:
-            raise SerializerError("serializer is already opened")
-
-    def close(self):
-        if self.closed is None:
-            raise SerializerError("serializer is not opened")
-        elif not self.closed:
-            self.emit(StreamEndEvent())
-            self.closed = True
-
-    #def __del__(self):
-    #    self.close()
-
-    def serialize(self, node):
-        if self.closed is None:
-            raise SerializerError("serializer is not opened")
-        elif self.closed:
-            raise SerializerError("serializer is closed")
-        self.emit(DocumentStartEvent(explicit=self.use_explicit_start,
-            version=self.use_version, tags=self.use_tags))
-        self.anchor_node(node)
-        self.serialize_node(node, None, None)
-        self.emit(DocumentEndEvent(explicit=self.use_explicit_end))
-        self.serialized_nodes = {}
-        self.anchors = {}
-        self.last_anchor_id = 0
-
-    def anchor_node(self, node):
-        if node in self.anchors:
-            if self.anchors[node] is None:
-                self.anchors[node] = self.generate_anchor(node)
-        else:
-            self.anchors[node] = None
-            if isinstance(node, SequenceNode):
-                for item in node.value:
-                    self.anchor_node(item)
-            elif isinstance(node, MappingNode):
-                for key, value in node.value:
-                    self.anchor_node(key)
-                    self.anchor_node(value)
-
-    def generate_anchor(self, node):
-        self.last_anchor_id += 1
-        return self.ANCHOR_TEMPLATE % self.last_anchor_id
-
-    def serialize_node(self, node, parent, index):
-        alias = self.anchors[node]
-        if node in self.serialized_nodes:
-            self.emit(AliasEvent(alias))
-        else:
-            self.serialized_nodes[node] = True
-            self.descend_resolver(parent, index)
-            if isinstance(node, ScalarNode):
-                detected_tag = self.resolve(ScalarNode, node.value, (True, False))
-                default_tag = self.resolve(ScalarNode, node.value, (False, True))
-                implicit = (node.tag == detected_tag), (node.tag == default_tag)
-                self.emit(ScalarEvent(alias, node.tag, implicit, node.value,
-                    style=node.style))
-            elif isinstance(node, SequenceNode):
-                implicit = (node.tag
-                            == self.resolve(SequenceNode, node.value, True))
-                self.emit(SequenceStartEvent(alias, node.tag, implicit,
-                    flow_style=node.flow_style))
-                index = 0
-                for item in node.value:
-                    self.serialize_node(item, node, index)
-                    index += 1
-                self.emit(SequenceEndEvent())
-            elif isinstance(node, MappingNode):
-                implicit = (node.tag
-                            == self.resolve(MappingNode, node.value, True))
-                self.emit(MappingStartEvent(alias, node.tag, implicit,
-                    flow_style=node.flow_style))
-                for key, value in node.value:
-                    self.serialize_node(key, node, None)
-                    self.serialize_node(value, node, key)
-                self.emit(MappingEndEvent())
-            self.ascend_resolver()
-
diff --git a/lib3/yaml/tokens.py b/lib3/yaml/tokens.py
deleted file mode 100644
index 4d0b48a..0000000
--- a/lib3/yaml/tokens.py
+++ /dev/null
@@ -1,104 +0,0 @@
-
-class Token(object):
-    def __init__(self, start_mark, end_mark):
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-    def __repr__(self):
-        attributes = [key for key in self.__dict__
-                if not key.endswith('_mark')]
-        attributes.sort()
-        arguments = ', '.join(['%s=%r' % (key, getattr(self, key))
-                for key in attributes])
-        return '%s(%s)' % (self.__class__.__name__, arguments)
-
-#class BOMToken(Token):
-#    id = '<byte order mark>'
-
-class DirectiveToken(Token):
-    id = '<directive>'
-    def __init__(self, name, value, start_mark, end_mark):
-        self.name = name
-        self.value = value
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-
-class DocumentStartToken(Token):
-    id = '<document start>'
-
-class DocumentEndToken(Token):
-    id = '<document end>'
-
-class StreamStartToken(Token):
-    id = '<stream start>'
-    def __init__(self, start_mark=None, end_mark=None,
-            encoding=None):
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.encoding = encoding
-
-class StreamEndToken(Token):
-    id = '<stream end>'
-
-class BlockSequenceStartToken(Token):
-    id = '<block sequence start>'
-
-class BlockMappingStartToken(Token):
-    id = '<block mapping start>'
-
-class BlockEndToken(Token):
-    id = '<block end>'
-
-class FlowSequenceStartToken(Token):
-    id = '['
-
-class FlowMappingStartToken(Token):
-    id = '{'
-
-class FlowSequenceEndToken(Token):
-    id = ']'
-
-class FlowMappingEndToken(Token):
-    id = '}'
-
-class KeyToken(Token):
-    id = '?'
-
-class ValueToken(Token):
-    id = ':'
-
-class BlockEntryToken(Token):
-    id = '-'
-
-class FlowEntryToken(Token):
-    id = ','
-
-class AliasToken(Token):
-    id = '<alias>'
-    def __init__(self, value, start_mark, end_mark):
-        self.value = value
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-
-class AnchorToken(Token):
-    id = '<anchor>'
-    def __init__(self, value, start_mark, end_mark):
-        self.value = value
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-
-class TagToken(Token):
-    id = '<tag>'
-    def __init__(self, value, start_mark, end_mark):
-        self.value = value
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-
-class ScalarToken(Token):
-    id = '<scalar>'
-    def __init__(self, value, plain, start_mark, end_mark, style=None):
-        self.value = value
-        self.plain = plain
-        self.start_mark = start_mark
-        self.end_mark = end_mark
-        self.style = style
-
diff --git a/packaging/build/libyaml.sh b/packaging/build/libyaml.sh
new file mode 100755
index 0000000..f33cffe
--- /dev/null
+++ b/packaging/build/libyaml.sh
@@ -0,0 +1,26 @@
+#!/bin/bash
+
+set -eux
+
+# build the requested version of libyaml locally
+echo "::group::fetch libyaml ${LIBYAML_REF}"
+git config --global advice.detachedHead false
+git clone --branch "$LIBYAML_REF" "$LIBYAML_REPO" libyaml
+pushd libyaml
+git reset --hard "$LIBYAML_REF"
+echo "::endgroup::"
+
+echo "::group::autoconf libyaml w/ static only"
+./bootstrap
+# build only a static library- reduces our reliance on auditwheel/delocate magic
+./configure --disable-dependency-tracking --with-pic --enable-shared=no
+echo "::endgroup::"
+
+echo "::group::build libyaml"
+make
+echo "::endgroup::"
+
+echo "::group::test built libyaml"
+make test-all
+echo "::endgroup::"
+popd
diff --git a/packaging/build/smoketest.py b/packaging/build/smoketest.py
new file mode 100644
index 0000000..7d799ce
--- /dev/null
+++ b/packaging/build/smoketest.py
@@ -0,0 +1,22 @@
+import sys
+import yaml
+
+
+def main():
+    # various smoke tests on an installed PyYAML with extension
+    if not getattr(yaml, '_yaml', None):
+        raise Exception('C extension is not available at `yaml._yaml`')
+
+    print('embedded libyaml version is {0}'.format(yaml._yaml.get_version_string()))
+
+    for loader, dumper in [(yaml.CLoader, yaml.CDumper), (yaml.Loader, yaml.Dumper)]:
+        testyaml = 'dude: mar'
+        loaded = yaml.load(testyaml, Loader=loader)
+        dumped = yaml.dump(loaded, Dumper=dumper)
+        if testyaml != dumped.strip():
+            raise Exception('roundtrip failed with {0}/{1}'.format(loader, dumper))
+    print('smoke test passed for {0}'.format(sys.executable))
+
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..2bf5ec8
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,3 @@
+[build-system]
+requires = ["setuptools", "wheel", "Cython"]
+build-backend = "setuptools.build_meta"
diff --git a/setup.cfg b/setup.cfg
deleted file mode 100644
index 067c6bc..0000000
--- a/setup.cfg
+++ /dev/null
@@ -1,29 +0,0 @@
-
-# The INCLUDE and LIB directories to build the '_yaml' extension.
-# You may also set them using the options '-I' and '-L'.
-[build_ext]
-
-# List of directories to search for 'yaml.h' (separated by ':').
-#include_dirs=/usr/local/include:../../include
-
-# List of directories to search for 'libyaml.a' (separated by ':').
-#library_dirs=/usr/local/lib:../../lib
-
-# An alternative compiler to build the extension.
-#compiler=mingw32
-
-# Additional preprocessor definitions might be required.
-#define=YAML_DECLARE_STATIC
-
-# The following options are used to build PyYAML Windows installer
-# for Python 2.5 on my PC:
-#include_dirs=../../../libyaml/tags/0.1.4/include
-#library_dirs=../../../libyaml/tags/0.1.4/win32/vs2003/output/release/lib
-#define=YAML_DECLARE_STATIC
-
-# The following options are used to build PyYAML Windows installer
-# for Python 2.6, 2.7, 3.0, 3.1 and 3.2 on my PC:
-#include_dirs=../../../libyaml/tags/0.1.4/include
-#library_dirs=../../../libyaml/tags/0.1.4/win32/vs2008/output/release/lib
-#define=YAML_DECLARE_STATIC
-
diff --git a/setup.py b/setup.py
index 479ff04..548b19f 100644
--- a/setup.py
+++ b/setup.py
@@ -1,6 +1,6 @@
 
 NAME = 'PyYAML'
-VERSION = '3.12'
+VERSION = '6.0'
 DESCRIPTION = "YAML parser and emitter for Python"
 LONG_DESCRIPTION = """\
 YAML is a data serialization format designed for human readability
@@ -18,27 +18,33 @@
 AUTHOR_EMAIL = 'xi@resolvent.net'
 LICENSE = "MIT"
 PLATFORMS = "Any"
-URL = "http://pyyaml.org/wiki/PyYAML"
-DOWNLOAD_URL = "http://pyyaml.org/download/pyyaml/%s-%s.tar.gz" % (NAME, VERSION)
+URL = "https://pyyaml.org/"
+DOWNLOAD_URL = "https://pypi.org/project/PyYAML/"
 CLASSIFIERS = [
     "Development Status :: 5 - Production/Stable",
     "Intended Audience :: Developers",
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
+    "Programming Language :: Cython",
     "Programming Language :: Python",
-    "Programming Language :: Python :: 2",
-    "Programming Language :: Python :: 2.6",
-    "Programming Language :: Python :: 2.7",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.4",
-    "Programming Language :: Python :: 3.5",
     "Programming Language :: Python :: 3.6",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: Implementation :: CPython",
     "Programming Language :: Python :: Implementation :: PyPy",
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Topic :: Text Processing :: Markup",
 ]
-
+PROJECT_URLS = {
+   'Bug Tracker': 'https://github.com/yaml/pyyaml/issues',
+   'CI': 'https://github.com/yaml/pyyaml/actions',
+   'Documentation': 'https://pyyaml.org/wiki/PyYAMLDocumentation',
+   'Mailing lists': 'http://lists.sourceforge.net/lists/listinfo/yaml-core',
+   'Source Code': 'https://github.com/yaml/pyyaml',
+}
 
 LIBYAML_CHECK = """
 #include <yaml.h>
@@ -58,30 +64,28 @@
 """
 
 
-import sys, os.path, platform
+import sys, os, os.path, pathlib, platform, shutil, tempfile, warnings
 
+# for newer setuptools, enable the embedded distutils before importing setuptools/distutils to avoid warnings
+os.environ['SETUPTOOLS_USE_DISTUTILS'] = 'local'
+
+from setuptools import setup, Command, Distribution as _Distribution, Extension as _Extension
+from setuptools.command.build_ext import build_ext as _build_ext
+# NB: distutils imports must remain below setuptools to ensure we use the embedded version
 from distutils import log
-from distutils.core import setup, Command
-from distutils.core import Distribution as _Distribution
-from distutils.core import Extension as _Extension
-from distutils.dir_util import mkpath
-from distutils.command.build_ext import build_ext as _build_ext
-from distutils.command.bdist_rpm import bdist_rpm as _bdist_rpm
 from distutils.errors import DistutilsError, CompileError, LinkError, DistutilsPlatformError
 
-if 'setuptools.extension' in sys.modules:
-    _Extension = sys.modules['setuptools.extension']._Extension
-    sys.modules['distutils.core'].Extension = _Extension
-    sys.modules['distutils.extension'].Extension = _Extension
-    sys.modules['distutils.command.build_ext'].Extension = _Extension
-
 with_cython = False
+if 'sdist' in sys.argv or os.environ.get('PYYAML_FORCE_CYTHON') == '1':
+    # we need cython here
+    with_cython = True
 try:
     from Cython.Distutils.extension import Extension as _Extension
     from Cython.Distutils import build_ext as _build_ext
     with_cython = True
 except ImportError:
-    pass
+    if with_cython:
+        raise
 
 try:
     from wheel.bdist_wheel import bdist_wheel
@@ -89,8 +93,21 @@
     bdist_wheel = None
 
 
-class Distribution(_Distribution):
+# on Windows, disable wheel generation warning noise
+windows_ignore_warnings = [
+"Unknown distribution option: 'python_requires'",
+"Config variable 'Py_DEBUG' is unset",
+"Config variable 'WITH_PYMALLOC' is unset",
+"Config variable 'Py_UNICODE_SIZE' is unset",
+"Cython directive 'language_level' not set"
+]
 
+if platform.system() == 'Windows':
+    for w in windows_ignore_warnings:
+        warnings.filterwarnings('ignore', w)
+
+
+class Distribution(_Distribution):
     def __init__(self, attrs=None):
         _Distribution.__init__(self, attrs)
         if not self.ext_modules:
@@ -121,10 +138,15 @@
 
     def ext_status(self, ext):
         implementation = platform.python_implementation()
-        if implementation != 'CPython':
+        if implementation not in ['CPython', 'PyPy']:
             return False
         if isinstance(ext, Extension):
-            with_ext = getattr(self, ext.attr_name)
+            # the "build by default" behavior is implemented by this returning None
+            with_ext = getattr(self, ext.attr_name) or os.environ.get('PYYAML_FORCE_{0}'.format(ext.feature_name.upper()))
+            try:
+                with_ext = int(with_ext)  # attempt coerce envvar to int
+            except TypeError:
+                pass
             return with_ext
         else:
             return True
@@ -216,27 +238,6 @@
                 log.warn("Error compiling module, falling back to pure Python")
 
 
-class bdist_rpm(_bdist_rpm):
-
-    def _make_spec_file(self):
-        argv0 = sys.argv[0]
-        features = []
-        for ext in self.distribution.ext_modules:
-            if not isinstance(ext, Extension):
-                continue
-            with_ext = getattr(self.distribution, ext.attr_name)
-            if with_ext is None:
-                continue
-            if with_ext:
-                features.append('--'+ext.option_name)
-            else:
-                features.append('--'+ext.neg_option_name)
-        sys.argv[0] = ' '.join([argv0]+features)
-        spec_file = _bdist_rpm._make_spec_file(self)
-        sys.argv[0] = argv0
-        return spec_file
-
-
 class test(Command):
 
     user_options = []
@@ -250,19 +251,32 @@
     def run(self):
         build_cmd = self.get_finalized_command('build')
         build_cmd.run()
-        sys.path.insert(0, build_cmd.build_lib)
-        if sys.version_info[0] < 3:
+
+        # running the tests this way can pollute the post-MANIFEST build sources
+        # (see https://github.com/yaml/pyyaml/issues/527#issuecomment-921058344)
+        # until we remove the test command, run tests from an ephemeral copy of the intermediate build sources
+        tempdir = tempfile.TemporaryDirectory(prefix='test_pyyaml')
+
+        try:
+            # have to create a subdir since we don't get dir_exists_ok on copytree until 3.8
+            temp_test_path = pathlib.Path(tempdir.name) / 'pyyaml'
+            shutil.copytree(build_cmd.build_lib, temp_test_path)
+            sys.path.insert(0, str(temp_test_path))
             sys.path.insert(0, 'tests/lib')
-        else:
-            sys.path.insert(0, 'tests/lib3')
-        import test_all
-        if not test_all.main([]):
-            raise DistutilsError("Tests failed")
+
+            import test_all
+            if not test_all.main([]):
+                raise DistutilsError("Tests failed")
+        finally:
+            try:
+                # this can fail under Windows; best-effort cleanup
+                tempdir.cleanup()
+            except Exception:
+                pass
 
 
 cmdclass = {
     'build_ext': build_ext,
-    'bdist_rpm': bdist_rpm,
     'test': test,
 }
 if bdist_wheel:
@@ -283,15 +297,17 @@
         url=URL,
         download_url=DOWNLOAD_URL,
         classifiers=CLASSIFIERS,
+        project_urls=PROJECT_URLS,
 
-        package_dir={'': {2: 'lib', 3: 'lib3'}[sys.version_info[0]]},
-        packages=['yaml'],
+        package_dir={'': 'lib'},
+        packages=['yaml', '_yaml'],
         ext_modules=[
-            Extension('_yaml', ['ext/_yaml.pyx'],
+            Extension('yaml._yaml', ['yaml/_yaml.pyx'],
                 'libyaml', "LibYAML bindings", LIBYAML_CHECK,
                 libraries=['yaml']),
         ],
 
         distclass=Distribution,
         cmdclass=cmdclass,
+        python_requires='>=3.6',
     )
diff --git a/tests/data/construct-python-name-module.code b/tests/data/construct-python-name-module.code
index 6f39148..b8a4b6f 100644
--- a/tests/data/construct-python-name-module.code
+++ b/tests/data/construct-python-name-module.code
@@ -1 +1 @@
-[str, yaml.Loader, yaml.dump, abs, yaml.tokens]
+[str, yaml.Loader, yaml.dump, abs, yaml.tokens, signal.Handlers]
diff --git a/tests/data/construct-python-name-module.data b/tests/data/construct-python-name-module.data
index f0c9712..f1a2c24 100644
--- a/tests/data/construct-python-name-module.data
+++ b/tests/data/construct-python-name-module.data
@@ -3,3 +3,4 @@
 - !!python/name:yaml.dump
 - !!python/name:abs
 - !!python/module:yaml.tokens
+- !!python/name:signal.Handlers
diff --git a/tests/data/construct-python-object.code b/tests/data/construct-python-object.code
index 7f1edf1..9e611e4 100644
--- a/tests/data/construct-python-object.code
+++ b/tests/data/construct-python-object.code
@@ -17,6 +17,8 @@
 Reduce(1, 'two', [3,3,3]),
 ReduceWithState(1, 'two', [3,3,3]),
 
+Slots(1, 'two', [3,3,3]),
+
 MyInt(3),
 MyList(3),
 MyDict(3),
diff --git a/tests/data/construct-python-object.data b/tests/data/construct-python-object.data
index bce8b2e..66797e4 100644
--- a/tests/data/construct-python-object.data
+++ b/tests/data/construct-python-object.data
@@ -16,6 +16,8 @@
 - !!python/object/apply:test_constructor.Reduce [1, two, [3,3,3]]
 - !!python/object/apply:test_constructor.ReduceWithState { args: [1, two], state: [3,3,3] }
 
+- !!python/object/new:test_constructor.Slots { state: !!python/tuple [null, { foo: 1, bar: 'two', baz: [3,3,3] } ] }
+
 - !!python/object/new:test_constructor.MyInt [3]
 - !!python/object/new:test_constructor.MyList { listitems: [~, ~, ~] }
 - !!python/object/new:test_constructor.MyDict { dictitems: {0, 1, 2} }
diff --git a/tests/data/emitting-unacceptable-unicode-character-bug-py2.code b/tests/data/emitting-unacceptable-unicode-character-bug.code
similarity index 100%
rename from tests/data/emitting-unacceptable-unicode-character-bug-py2.code
rename to tests/data/emitting-unacceptable-unicode-character-bug.code
diff --git a/tests/data/emitting-unacceptable-unicode-character-bug-py2.data b/tests/data/emitting-unacceptable-unicode-character-bug.data
similarity index 100%
rename from tests/data/emitting-unacceptable-unicode-character-bug-py2.data
rename to tests/data/emitting-unacceptable-unicode-character-bug.data
diff --git a/tests/data/emitting-unacceptable-unicode-character-bug-py2.skip-ext b/tests/data/emitting-unacceptable-unicode-character-bug.skip-ext
similarity index 100%
rename from tests/data/emitting-unacceptable-unicode-character-bug-py2.skip-ext
rename to tests/data/emitting-unacceptable-unicode-character-bug.skip-ext
diff --git a/tests/data/mapping.sort b/tests/data/mapping.sort
new file mode 100644
index 0000000..802ba1a
--- /dev/null
+++ b/tests/data/mapping.sort
@@ -0,0 +1,6 @@
+z: 1
+a: 2
+y: 3
+b: 4
+x: 5
+c: 6
diff --git a/tests/data/mapping.sorted b/tests/data/mapping.sorted
new file mode 100644
index 0000000..b3dd346
--- /dev/null
+++ b/tests/data/mapping.sorted
@@ -0,0 +1,6 @@
+a: 2
+b: 4
+c: 6
+x: 5
+y: 3
+z: 1
diff --git a/tests/data/multi-constructor.code b/tests/data/multi-constructor.code
new file mode 100644
index 0000000..590d852
--- /dev/null
+++ b/tests/data/multi-constructor.code
@@ -0,0 +1,4 @@
+[
+    {'Tag1': ['a', 1, 'b', 2]},
+    {'Tag2': ['a', 1, 'b', 2]},
+]
diff --git a/tests/data/multi-constructor.multi b/tests/data/multi-constructor.multi
new file mode 100644
index 0000000..4f5d71f
--- /dev/null
+++ b/tests/data/multi-constructor.multi
@@ -0,0 +1,3 @@
+---
+- !Tag1 [a, 1, b, 2]
+- !!Tag2 [a, 1, b, 2]
diff --git a/tests/data/myfullloader.subclass_blacklist b/tests/data/myfullloader.subclass_blacklist
new file mode 100644
index 0000000..555a2b3
--- /dev/null
+++ b/tests/data/myfullloader.subclass_blacklist
@@ -0,0 +1,5 @@
+- !!python/object/new:yaml.MappingNode
+  args:
+  state:
+    mymethod: test
+    wrong_method: test2
diff --git a/tests/data/overwrite-state-new-constructor.loader-error b/tests/data/overwrite-state-new-constructor.loader-error
new file mode 100644
index 0000000..8d224f1
--- /dev/null
+++ b/tests/data/overwrite-state-new-constructor.loader-error
@@ -0,0 +1,5 @@
+- !!python/object/new:yaml.MappingNode
+  args:
+  state:
+    extend: test
+    __test__: test
diff --git a/tests/data/timestamp-bugs.code b/tests/data/timestamp-bugs.code
index b1d6e9c..e2c84cc 100644
--- a/tests/data/timestamp-bugs.code
+++ b/tests/data/timestamp-bugs.code
@@ -1,8 +1,8 @@
 [
-    datetime.datetime(2001, 12, 15, 3, 29, 43, 100000),
-    datetime.datetime(2001, 12, 14, 16, 29, 43, 100000),
-    datetime.datetime(2001, 12, 14, 21, 59, 43, 1010),
-    datetime.datetime(2001, 12, 14, 21, 59, 43, 0, FixedOffset(60, "+1")),
-    datetime.datetime(2001, 12, 14, 21, 59, 43, 0, FixedOffset(-90, "-1:30")),
-    datetime.datetime(2005, 7, 8, 17, 35, 4, 517600),
+    [datetime.datetime(2001, 12, 15, 3, 29, 43, 100000), 'UTC-05:30'],
+    [datetime.datetime(2001, 12, 14, 16, 29, 43, 100000), 'UTC+05:30'],
+    [datetime.datetime(2001, 12, 14, 21, 59, 43, 1010), None],
+    [datetime.datetime(2001, 12, 14, 21, 59, 43, 0, FixedOffset(60, "+1")), 'UTC+01:00'],
+    [datetime.datetime(2001, 12, 14, 21, 59, 43, 0, FixedOffset(-90, "-1:30")), 'UTC-01:30'],
+    [datetime.datetime(2005, 7, 8, 17, 35, 4, 517600), None],
 ]
diff --git a/tests/data/timestamp-bugs.data b/tests/data/timestamp-bugs.data
index 721d290..b243d0d 100644
--- a/tests/data/timestamp-bugs.data
+++ b/tests/data/timestamp-bugs.data
@@ -1,6 +1,12 @@
-- 2001-12-14 21:59:43.10 -5:30
-- 2001-12-14 21:59:43.10 +5:30
-- 2001-12-14 21:59:43.00101
-- 2001-12-14 21:59:43+1
-- 2001-12-14 21:59:43-1:30
-- 2005-07-08 17:35:04.517600
+- !MyTime
+  - 2001-12-14 21:59:43.10 -5:30
+- !MyTime
+  - 2001-12-14 21:59:43.10 +5:30
+- !MyTime
+  - 2001-12-14 21:59:43.00101
+- !MyTime
+  - 2001-12-14 21:59:43+1
+- !MyTime
+  - 2001-12-14 21:59:43-1:30
+- !MyTime
+  - 2005-07-08 17:35:04.517600
diff --git a/tests/data/yaml11.schema b/tests/data/yaml11.schema
new file mode 100644
index 0000000..e2791aa
--- /dev/null
+++ b/tests/data/yaml11.schema
@@ -0,0 +1,264 @@
+# https://github.com/perlpunk/yaml-test-schema/blob/master/data/schema-yaml11.yaml
+---
+'!!bool FALSE': ['bool', 'false()', 'false']
+'!!bool False': ['bool', 'false()', 'false']
+'!!bool N': ['bool', 'false()', "false"]
+'!!bool NO': ['bool', 'false()', "false"]
+'!!bool No': ['bool', 'false()', "false"]
+'!!bool OFF': ['bool', 'false()', "false"]
+'!!bool ON': ['bool', 'true()', "true"]
+'!!bool Off': ['bool', 'false()', "false"]
+'!!bool On': ['bool', 'true()', "true"]
+'!!bool TRUE': ['bool', 'true()', 'true']
+'!!bool True': ['bool', 'true()', 'true']
+'!!bool Y': ['bool', 'true()', "true"]
+'!!bool YES': ['bool', 'true()', "true"]
+'!!bool Yes': ['bool', 'true()', "true"]
+'!!bool false': ['bool', 'false()', 'false']
+'!!bool n': ['bool', 'false()', "false"]
+'!!bool no': ['bool', 'false()', "false"]
+'!!bool off': ['bool', 'false()', "false"]
+'!!bool on': ['bool', 'true()', "true"]
+'!!bool true': ['bool', 'true()', 'true']
+'!!bool y': ['bool', 'true()', "true"]
+'!!bool yes': ['bool', 'true()', "true"]
+'!!float +.INF': ['inf', 'inf()', '.inf']
+'!!float +.Inf': ['inf', 'inf()', '.inf']
+'!!float +.inf': ['inf', 'inf()', '.inf']
+'!!float +0.3e+3': ['float', '300.0', '300.0']
+'!!float -.INF': ['inf', 'inf-neg()', '-.inf']
+'!!float -.Inf': ['inf', 'inf-neg()', '-.inf']
+'!!float -.inf': ['inf', 'inf-neg()', '-.inf']
+'!!float -3.14': ['float', '-3.14', '-3.14']
+'!!float .0': ['float', '0.0', '0.0']
+'!!float .14': ['float', '0.14', '0.14']
+'!!float .1_4': ['float', '0.14', '0.14']
+'!!float .3E-1': ['float', '0.03', '0.03']
+'!!float .3e+3': ['float', '300.0', '300.0']
+'!!float .INF': ['inf', 'inf()', '.inf']
+'!!float .Inf': ['inf', 'inf()', '.inf']
+'!!float .NAN': ['nan', 'nan()', '.nan']
+'!!float .NaN': ['nan', 'nan()', '.nan']
+'!!float .inf': ['inf', 'inf()', '.inf']
+'!!float .nan': ['nan', 'nan()', '.nan']
+'!!float 0.0': ['float', '0.0', '0.0']
+'!!float 001.23': ['float', '1.23', '1.23']
+'!!float 190:20:30.15': ['float', '685230.15', '685230.15']
+'!!float 3.': ['float', '3.0', '3.0']
+'!!float 3.14': ['float', '3.14', '3.14']
+'!!float 3.3e+3': ['float', '3300.0', '3300.0']
+'!!float 85.230_15e+03': ['float', '85230.15', '85230.15']
+'!!float 85_230.15': ['float', '85230.15', '85230.15']
+'!!int +0': ['int', '0', '0']
+'!!int +0100_200': ['int', '32896', '32896']
+'!!int +0b100': ['int', '4', '4']
+'!!int +190:20:30': ['int', '685230', '685230']
+'!!int +23': ['int', '23', '23']
+'!!int -0': ['int', '0', '0']
+'!!int -0100_200': ['int', '-32896', '-32896']
+'!!int -0b101': ['int', '-5', '-5']
+'!!int -0x30': ['int', '-48', '-48']
+'!!int -190:20:30': ['int', '-685230', '-685230']
+'!!int -23': ['int', '-23', '-23']
+'!!int 0': ['int', '0', '0']
+'!!int 00': ['int', '0', '0']
+'!!int 0011': ['int', '9', '9']
+'!!int 010': ['int', '8', '8']
+'!!int 02_0': ['int', '16', '16']
+'!!int 07': ['int', '7', '7']
+'!!int 0b0': ['int', '0', '0']
+'!!int 0b100_101': ['int', '37', '37']
+'!!int 0x0': ['int', '0', '0']
+'!!int 0x10': ['int', '16', '16']
+'!!int 0x2_0': ['int', '32', '32']
+'!!int 0x42': ['int', '66', '66']
+'!!int 0xa': ['int', '10', '10']
+'!!int 100_000': ['int', '100000', '100000']
+'!!int 190:20:30': ['int', '685230', '685230']
+'!!int 23': ['int', '23', '23']
+'!!null #empty': ['null', 'null()', "null"]
+'!!null NULL': ['null', 'null()', "null"]
+'!!null Null': ['null', 'null()', "null"]
+'!!null null': ['null', 'null()', 'null']
+'!!null ~': ['null', 'null()', 'null']
+'!!str #empty': ['str', '', "''"]
+'!!str +.INF': ['str', '+.INF', "'+.INF'"]
+'!!str +.Inf': ['str', '+.Inf', "'+.Inf'"]
+'!!str +.inf': ['str', '+.inf', "'+.inf'"]
+'!!str +0': ['str', '+0', "'+0'"]
+'!!str +0.3e+3': ['str', '+0.3e+3', "'+0.3e+3'"]
+'!!str +0.3e3': ['str', '+0.3e3', "+0.3e3"]
+'!!str +0100_200': ['str', '+0100_200', "'+0100_200'"]
+'!!str +0b100': ['str', '+0b100', "'+0b100'"]
+'!!str +190:20:30': ['str', '+190:20:30', "'+190:20:30'"]
+'!!str +23': ['str', '+23', "'+23'"]
+'!!str -.INF': ['str', '-.INF', "'-.INF'"]
+'!!str -.Inf': ['str', '-.Inf', "'-.Inf'"]
+'!!str -.inf': ['str', '-.inf', "'-.inf'"]
+'!!str -0': ['str', '-0', "'-0'"]
+'!!str -0100_200': ['str', '-0100_200', "'-0100_200'"]
+'!!str -0b101': ['str', '-0b101', "'-0b101'"]
+'!!str -0x30': ['str', '-0x30', "'-0x30'"]
+'!!str -190:20:30': ['str', '-190:20:30', "'-190:20:30'"]
+'!!str -23': ['str', '-23', "'-23'"]
+'!!str -3.14': ['str', '-3.14', "'-3.14'"]
+'!!str .': ['str', '.', '.']
+'!!str .0': ['str', '.0', "'.0'"]
+'!!str .14': ['str', '.14', "'.14'"]
+'!!str .1_4': ['str', '.1_4', "'.1_4'"]
+'!!str .3E-1': ['str', '.3E-1', "'.3E-1'"]
+'!!str .3e+3': ['str', '.3e+3', "'.3e+3'"]
+'!!str .3e3': ['str', '.3e3', ".3e3"]
+'!!str .INF': ['str', '.INF', "'.INF'"]
+'!!str .Inf': ['str', '.Inf', "'.Inf'"]
+'!!str .NAN': ['str', '.NAN', "'.NAN'"]
+'!!str .NaN': ['str', '.NaN', "'.NaN'"]
+'!!str ._': ['str', '._', '._']
+'!!str ._14': ['str', '._14', '._14']
+'!!str .inf': ['str', '.inf', "'.inf'"]
+'!!str .nan': ['str', '.nan', "'.nan'"]
+'!!str 0': ['str', '0', "'0'"]
+'!!str 0.0': ['str', '0.0', "'0.0'"]
+'!!str 0.3e3': ['str', '0.3e3', "0.3e3"]
+'!!str 00': ['str', '00', "'00'"]
+'!!str 001.23': ['str', '001.23', "'001.23'"]
+'!!str 0011': ['str', '0011', "'0011'"]
+'!!str 010': ['str', '010', "'010'"]
+'!!str 02_0': ['str', '02_0', "'02_0'"]
+'!!str 07': ['str', '07', "'07'"]
+'!!str 0b0': ['str', '0b0', "'0b0'"]
+'!!str 0b100_101': ['str', '0b100_101', "'0b100_101'"]
+'!!str 0o0': ['str', '0o0', "0o0"]
+'!!str 0o10': ['str', '0o10', "0o10"]
+'!!str 0o7': ['str', '0o7', "0o7"]
+'!!str 0x0': ['str', '0x0', "'0x0'"]
+'!!str 0x2_0': ['str', '0x2_0', "'0x2_0'"]
+'!!str 0xa': ['str', '0xa', "'0xa'"]
+'!!str 100_000': ['str', '100_000', "'100_000'"]
+'!!str 190:20:30': ['str', '190:20:30', "'190:20:30'"]
+'!!str 190:20:30.15': ['str', '190:20:30.15', "'190:20:30.15'"]
+'!!str 23': ['str', '23', "'23'"]
+'!!str 3.': ['str', '3.', "'3.'"]
+'!!str 3.14': ['str', '3.14', "'3.14'"]
+'!!str 3.3e+3': ['str', '3.3e+3', "'3.3e+3'"]
+'!!str 85.230_15e+03': ['str', '85.230_15e+03', "'85.230_15e+03'"]
+'!!str 85_230.15': ['str', '85_230.15', "'85_230.15'"]
+'!!str FALSE': ['str', 'FALSE', "'FALSE'"]
+'!!str False': ['str', 'False', "'False'"]
+'!!str N': ['str', 'N', "'N'"]
+'!!str NO': ['str', 'NO', "'NO'"]
+'!!str NULL': ['str', 'NULL', "'NULL'"]
+'!!str Null': ['str', 'Null', "'Null'"]
+'!!str OFF': ['str', 'OFF', "'OFF'"]
+'!!str ON': ['str', 'ON', "'ON'"]
+'!!str Off': ['str', 'Off', "'Off'"]
+'!!str On': ['str', 'On', "'On'"]
+'!!str TRUE': ['str', 'TRUE', "'TRUE'"]
+'!!str True': ['str', 'True', "'True'"]
+'!!str Y': ['str', 'Y', "'Y'"]
+'!!str YES': ['str', 'YES', "'YES'"]
+'!!str Yes': ['str', 'Yes', "'Yes'"]
+'!!str _._': ['str', '_._', '_._']
+'!!str false': ['str', 'false', "'false'"]
+'!!str n': ['str', 'n', "'n'"]
+'!!str no': ['str', 'no', "'no'"]
+'!!str null': ['str', 'null', "'null'"]
+'!!str off': ['str', 'off', "'off'"]
+'!!str on': ['str', 'on', "'on'"]
+'!!str true': ['str', 'true', "'true'"]
+'!!str y': ['str', 'y', "'y'"]
+'!!str yes': ['str', 'yes', "'yes'"]
+'!!str ~': ['str', '~', "'~'"]
+'#empty': ['null', 'null()', "null"]
+'+.INF': ['inf', 'inf()', '.inf']
+'+.Inf': ['inf', 'inf()', '.inf']
+'+.inf': ['inf', 'inf()', '.inf']
+'+0': ['int', '0', '0']
+'+0.3e+3': ['float', '300.0', '300.0']
+'+0.3e3': ['str', '+0.3e3', '+0.3e3']
+'+0100_200': ['int', '32896', '32896']
+'+0b100': ['int', '4', '4']
+'+190:20:30': ['int', '685230', '685230']
+'+23': ['int', '23', '23']
+'+3.14': ['float', '3.14', '3.14']
+'-.INF': ['inf', 'inf-neg()', '-.inf']
+'-.Inf': ['inf', 'inf-neg()', '-.inf']
+'-.inf': ['inf', 'inf-neg()', '-.inf']
+'-0': ['int', '0', '0']
+'-0100_200': ['int', '-32896', '-32896']
+'-0b101': ['int', '-5', '-5']
+'-0x30': ['int', '-48', '-48']
+'-190:20:30': ['int', '-685230', '-685230']
+'-23': ['int', '-23', '-23']
+'-3.14': ['float', '-3.14', '-3.14']
+'.': ['str', '.', '.']
+'.0': ['float', '0.0', '0.0']
+'.14': ['float', '0.14', '0.14']
+'.1_4': ['float', '0.14', '0.14']
+'.3E-1': ['float', '0.03', '0.03']
+'.3e+3': ['float', '300.0', '300.0']
+'.3e3': ['str', '.3e3', '.3e3']
+'.INF': ['inf', 'inf()', '.inf']
+'.Inf': ['inf', 'inf()', '.inf']
+'.NAN': ['nan', 'nan()', '.nan']
+'.NaN': ['nan', 'nan()', '.nan']
+'._': ['str', '._', '._']
+'._14': ['str', '._14', '._14']
+'.inf': ['inf', 'inf()', '.inf']
+'.nan': ['nan', 'nan()', '.nan']
+'0': ['int', '0', '0']
+'0.0': ['float', '0.0', '0.0']
+'0.3e3': ['str', '0.3e3', '0.3e3']
+'00': ['int', '0', '0']
+'001.23': ['float', '1.23', '1.23']
+'0011': ['int', '9', '9']
+'010': ['int', '8', '8']
+'02_0': ['int', '16', '16']
+'07': ['int', '7', '7']
+'08': ['str', '08', '08']
+'0b0': ['int', '0', '0']
+'0b100_101': ['int', '37', '37']
+'0o0': ['str', '0o0', '0o0']
+'0o10': ['str', '0o10', '0o10']
+'0o7': ['str', '0o7', '0o7']
+'0x0': ['int', '0', '0']
+'0x10': ['int', '16', '16']
+'0x2_0': ['int', '32', '32']
+'0x42': ['int', '66', '66']
+'0xa': ['int', '10', '10']
+'100_000': ['int', '100000', '100000']
+'190:20:30': ['int', '685230', '685230']
+'190:20:30.15': ['float', '685230.15', '685230.15']
+'23': ['int', '23', '23']
+'3.': ['float', '3.0', '3.0']
+'3.14': ['float', '3.14', '3.14']
+'3.3e+3': ['float', '3300', '3300.0']
+'3e3': ['str', '3e3', '3e3']
+'85.230_15e+03': ['float', '85230.15', '85230.15']
+'85_230.15': ['float', '85230.15', '85230.15']
+'FALSE': ['bool', 'false()', 'false']
+'False': ['bool', 'false()', 'false']
+'N': ['bool', 'false()', "false"]
+'NO': ['bool', 'false()', "false"]
+'NULL': ['null', 'null()', "null"]
+'Null': ['null', 'null()', "null"]
+'OFF': ['bool', 'false()', "false"]
+'ON': ['bool', 'true()', "true"]
+'Off': ['bool', 'false()', "false"]
+'On': ['bool', 'true()', "true"]
+'TRUE': ['bool', 'true()', 'true']
+'True': ['bool', 'true()', 'true']
+'Y': ['bool', 'true()', "true"]
+'YES': ['bool', 'true()', "true"]
+'Yes': ['bool', 'true()', "true"]
+'_._': ['str', '_._', '_._']
+'false': ['bool', 'false()', 'false']
+'n': ['bool', 'false()', "false"]
+'no': ['bool', 'false()', "false"]
+'null': ['null', 'null()', "null"]
+'off': ['bool', 'false()', "false"]
+'on': ['bool', 'true()', "true"]
+'true': ['bool', 'true()', 'true']
+'y': ['bool', 'true()', "true"]
+'yes': ['bool', 'true()', "true"]
+'~': ['null', 'null()', "null"]
diff --git a/tests/data/yaml11.schema-skip b/tests/data/yaml11.schema-skip
new file mode 100644
index 0000000..2d78a61
--- /dev/null
+++ b/tests/data/yaml11.schema-skip
@@ -0,0 +1,7 @@
+load: {
+  'Y': 1, 'y': 1, 'N': 1, 'n': 1,
+  '!!bool Y': 1, '!!bool N': 1, '!!bool n': 1, '!!bool y': 1,
+  }
+dump: {
+  '!!str N': 1, '!!str Y': 1, '!!str n': 1, '!!str y': 1,
+  }
diff --git a/tests/lib/canonical.py b/tests/lib/canonical.py
index 020e6db..a8b4e3a 100644
--- a/tests/lib/canonical.py
+++ b/tests/lib/canonical.py
@@ -7,10 +7,12 @@
 class CanonicalScanner:
 
     def __init__(self, data):
-        try:
-            self.data = unicode(data, 'utf-8')+u'\0'
-        except UnicodeDecodeError:
-            raise CanonicalError("utf-8 stream is expected")
+        if isinstance(data, bytes):
+            try:
+                data = data.decode('utf-8')
+            except UnicodeDecodeError:
+                raise CanonicalError("utf-8 stream is expected")
+        self.data = data+'\0'
         self.index = 0
         self.tokens = []
         self.scanned = False
@@ -49,63 +51,63 @@
         while True:
             self.find_token()
             ch = self.data[self.index]
-            if ch == u'\0':
+            if ch == '\0':
                 self.tokens.append(yaml.StreamEndToken(None, None))
                 break
-            elif ch == u'%':
+            elif ch == '%':
                 self.tokens.append(self.scan_directive())
-            elif ch == u'-' and self.data[self.index:self.index+3] == u'---':
+            elif ch == '-' and self.data[self.index:self.index+3] == '---':
                 self.index += 3
                 self.tokens.append(yaml.DocumentStartToken(None, None))
-            elif ch == u'[':
+            elif ch == '[':
                 self.index += 1
                 self.tokens.append(yaml.FlowSequenceStartToken(None, None))
-            elif ch == u'{':
+            elif ch == '{':
                 self.index += 1
                 self.tokens.append(yaml.FlowMappingStartToken(None, None))
-            elif ch == u']':
+            elif ch == ']':
                 self.index += 1
                 self.tokens.append(yaml.FlowSequenceEndToken(None, None))
-            elif ch == u'}':
+            elif ch == '}':
                 self.index += 1
                 self.tokens.append(yaml.FlowMappingEndToken(None, None))
-            elif ch == u'?':
+            elif ch == '?':
                 self.index += 1
                 self.tokens.append(yaml.KeyToken(None, None))
-            elif ch == u':':
+            elif ch == ':':
                 self.index += 1
                 self.tokens.append(yaml.ValueToken(None, None))
-            elif ch == u',':
+            elif ch == ',':
                 self.index += 1
                 self.tokens.append(yaml.FlowEntryToken(None, None))
-            elif ch == u'*' or ch == u'&':
+            elif ch == '*' or ch == '&':
                 self.tokens.append(self.scan_alias())
-            elif ch == u'!':
+            elif ch == '!':
                 self.tokens.append(self.scan_tag())
-            elif ch == u'"':
+            elif ch == '"':
                 self.tokens.append(self.scan_scalar())
             else:
                 raise CanonicalError("invalid token")
         self.scanned = True
 
-    DIRECTIVE = u'%YAML 1.1'
+    DIRECTIVE = '%YAML 1.1'
 
     def scan_directive(self):
         if self.data[self.index:self.index+len(self.DIRECTIVE)] == self.DIRECTIVE and \
-                self.data[self.index+len(self.DIRECTIVE)] in u' \n\0':
+                self.data[self.index+len(self.DIRECTIVE)] in ' \n\0':
             self.index += len(self.DIRECTIVE)
             return yaml.DirectiveToken('YAML', (1, 1), None, None)
         else:
             raise CanonicalError("invalid directive")
 
     def scan_alias(self):
-        if self.data[self.index] == u'*':
+        if self.data[self.index] == '*':
             TokenClass = yaml.AliasToken
         else:
             TokenClass = yaml.AnchorToken
         self.index += 1
         start = self.index
-        while self.data[self.index] not in u', \n\0':
+        while self.data[self.index] not in ', \n\0':
             self.index += 1
         value = self.data[start:self.index]
         return TokenClass(value, None, None)
@@ -113,17 +115,17 @@
     def scan_tag(self):
         self.index += 1
         start = self.index
-        while self.data[self.index] not in u' \n\0':
+        while self.data[self.index] not in ' \n\0':
             self.index += 1
         value = self.data[start:self.index]
         if not value:
-            value = u'!'
-        elif value[0] == u'!':
+            value = '!'
+        elif value[0] == '!':
             value = 'tag:yaml.org,2002:'+value[1:]
-        elif value[0] == u'<' and value[-1] == u'>':
+        elif value[0] == '<' and value[-1] == '>':
             value = value[1:-1]
         else:
-            value = u'!'+value
+            value = '!'+value
         return yaml.TagToken(value, None, None)
 
     QUOTE_CODES = {
@@ -133,23 +135,22 @@
     }
 
     QUOTE_REPLACES = {
-        u'\\': u'\\',
-        u'\"': u'\"',
-        u' ': u' ',
-        u'a': u'\x07',
-        u'b': u'\x08',
-        u'e': u'\x1B',
-        u'f': u'\x0C',
-        u'n': u'\x0A',
-        u'r': u'\x0D',
-        u't': u'\x09',
-        u'v': u'\x0B',
-        u'N': u'\u0085',
-        u'L': u'\u2028',
-        u'P': u'\u2029',
-        u'_': u'_',
-        u'0': u'\x00',
-
+        '\\': '\\',
+        '\"': '\"',
+        ' ': ' ',
+        'a': '\x07',
+        'b': '\x08',
+        'e': '\x1B',
+        'f': '\x0C',
+        'n': '\x0A',
+        'r': '\x0D',
+        't': '\x09',
+        'v': '\x0B',
+        'N': '\u0085',
+        'L': '\u2028',
+        'P': '\u2029',
+        '_': '_',
+        '0': '\x00',
     }
 
     def scan_scalar(self):
@@ -157,32 +158,32 @@
         chunks = []
         start = self.index
         ignore_spaces = False
-        while self.data[self.index] != u'"':
-            if self.data[self.index] == u'\\':
+        while self.data[self.index] != '"':
+            if self.data[self.index] == '\\':
                 ignore_spaces = False
                 chunks.append(self.data[start:self.index])
                 self.index += 1
                 ch = self.data[self.index]
                 self.index += 1
-                if ch == u'\n':
+                if ch == '\n':
                     ignore_spaces = True
                 elif ch in self.QUOTE_CODES:
                     length = self.QUOTE_CODES[ch]
                     code = int(self.data[self.index:self.index+length], 16)
-                    chunks.append(unichr(code))
+                    chunks.append(chr(code))
                     self.index += length
                 else:
                     if ch not in self.QUOTE_REPLACES:
                         raise CanonicalError("invalid escape code")
                     chunks.append(self.QUOTE_REPLACES[ch])
                 start = self.index
-            elif self.data[self.index] == u'\n':
+            elif self.data[self.index] == '\n':
                 chunks.append(self.data[start:self.index])
-                chunks.append(u' ')
+                chunks.append(' ')
                 self.index += 1
                 start = self.index
                 ignore_spaces = True
-            elif ignore_spaces and self.data[self.index] == u' ':
+            elif ignore_spaces and self.data[self.index] == ' ':
                 self.index += 1
                 start = self.index
             else:
@@ -190,17 +191,17 @@
                 self.index += 1
         chunks.append(self.data[start:self.index])
         self.index += 1
-        return yaml.ScalarToken(u''.join(chunks), False, None, None)
+        return yaml.ScalarToken(''.join(chunks), False, None, None)
 
     def find_token(self):
         found = False
         while not found:
-            while self.data[self.index] in u' \t':
+            while self.data[self.index] in ' \t':
                 self.index += 1
-            if self.data[self.index] == u'#':
-                while self.data[self.index] != u'\n':
+            if self.data[self.index] == '#':
+                while self.data[self.index] != '\n':
                     self.index += 1
-            if self.data[self.index] == u'\n':
+            if self.data[self.index] == '\n':
                 self.index += 1
             else:
                 found = True
diff --git a/tests/lib/test_appliance.py b/tests/lib/test_appliance.py
index f69412c..0c5cda1 100644
--- a/tests/lib/test_appliance.py
+++ b/tests/lib/test_appliance.py
@@ -10,9 +10,7 @@
     for collection in collections:
         if not isinstance(collection, dict):
             collection = vars(collection)
-        keys = collection.keys()
-        keys.sort()
-        for key in keys:
+        for key in sorted(collection):
             value = collection[key]
             if isinstance(value, types.FunctionType) and hasattr(value, 'unittest'):
                 functions.append(value)
@@ -23,11 +21,10 @@
     for filename in os.listdir(directory):
         if os.path.isfile(os.path.join(directory, filename)):
             base, ext = os.path.splitext(filename)
-            if base.endswith('-py3'):
+            if base.endswith('-py2'):
                 continue
             filenames.setdefault(base, []).append(ext)
-    filenames = filenames.items()
-    filenames.sort()
+    filenames = sorted(filenames.items())
     return filenames
 
 def parse_arguments(args):
@@ -54,16 +51,13 @@
     return include_functions, include_filenames, verbose
 
 def execute(function, filenames, verbose):
-    if hasattr(function, 'unittest_name'):
-        name = function.unittest_name
-    else:
-        name = function.func_name
+    name = function.__name__
     if verbose:
         sys.stdout.write('='*75+'\n')
         sys.stdout.write('%s(%s)...\n' % (name, ', '.join(filenames)))
     try:
         function(verbose=verbose, *filenames)
-    except Exception, exc:
+    except Exception as exc:
         info = sys.exc_info()
         if isinstance(exc, AssertionError):
             kind = 'FAILURE'
@@ -109,7 +103,8 @@
         for filename in filenames:
             sys.stdout.write('-'*75+'\n')
             sys.stdout.write('%s:\n' % filename)
-            data = open(filename, 'rb').read()
+            with open(filename, 'r', errors='replace') as file:
+                data = file.read()
             sys.stdout.write(data)
             if data and data[-1] != '\n':
                 sys.stdout.write('\n')
@@ -127,9 +122,9 @@
     include_functions, include_filenames, verbose = parse_arguments(args)
     results = []
     for function in test_functions:
-        if include_functions and function.func_name not in include_functions:
+        if include_functions and function.__name__ not in include_functions:
             continue
-        if function.unittest:
+        if function.unittest and function.unittest is not True:
             for base, exts in test_filenames:
                 if include_filenames and base not in include_filenames:
                     continue
diff --git a/tests/lib/test_build.py b/tests/lib/test_build.py
index 901e8ed..df3f943 100644
--- a/tests/lib/test_build.py
+++ b/tests/lib/test_build.py
@@ -2,7 +2,7 @@
 if __name__ == '__main__':
     import sys, os, distutils.util
     build_lib = 'build/lib'
-    build_lib_ext = os.path.join('build', 'lib.%s-%s' % (distutils.util.get_platform(), sys.version[0:3]))
+    build_lib_ext = os.path.join('build', 'lib.{}-{}.{}'.format(distutils.util.get_platform(), *sys.version_info))
     sys.path.insert(0, build_lib)
     sys.path.insert(0, build_lib_ext)
     import test_yaml, test_appliance
diff --git a/tests/lib/test_build_ext.py b/tests/lib/test_build_ext.py
index ff195d5..fa843f6 100644
--- a/tests/lib/test_build_ext.py
+++ b/tests/lib/test_build_ext.py
@@ -3,7 +3,7 @@
 if __name__ == '__main__':
     import sys, os, distutils.util
     build_lib = 'build/lib'
-    build_lib_ext = os.path.join('build', 'lib.%s-%s' % (distutils.util.get_platform(), sys.version[0:3]))
+    build_lib_ext = os.path.join('build', 'lib.{}-{}.{}'.format(distutils.util.get_platform(), *sys.version_info))
     sys.path.insert(0, build_lib)
     sys.path.insert(0, build_lib_ext)
     import test_yaml_ext, test_appliance
diff --git a/tests/lib/test_canonical.py b/tests/lib/test_canonical.py
index a851ef2..7bded81 100644
--- a/tests/lib/test_canonical.py
+++ b/tests/lib/test_canonical.py
@@ -2,32 +2,35 @@
 import yaml, canonical
 
 def test_canonical_scanner(canonical_filename, verbose=False):
-    data = open(canonical_filename, 'rb').read()
+    with open(canonical_filename, 'rb') as file:
+        data = file.read()
     tokens = list(yaml.canonical_scan(data))
     assert tokens, tokens
     if verbose:
         for token in tokens:
-            print token
+            print(token)
 
 test_canonical_scanner.unittest = ['.canonical']
 
 def test_canonical_parser(canonical_filename, verbose=False):
-    data = open(canonical_filename, 'rb').read()
+    with open(canonical_filename, 'rb') as file:
+        data = file.read()
     events = list(yaml.canonical_parse(data))
     assert events, events
     if verbose:
         for event in events:
-            print event
+            print(event)
 
 test_canonical_parser.unittest = ['.canonical']
 
 def test_canonical_error(data_filename, canonical_filename, verbose=False):
-    data = open(data_filename, 'rb').read()
+    with open(data_filename, 'rb') as file:
+        data = file.read()
     try:
         output = list(yaml.canonical_load_all(data))
-    except yaml.YAMLError, exc:
+    except yaml.YAMLError as exc:
         if verbose:
-            print exc
+            print(exc)
     else:
         raise AssertionError("expected an exception")
 
diff --git a/tests/lib/test_constructor.py b/tests/lib/test_constructor.py
index 12d5391..0783a21 100644
--- a/tests/lib/test_constructor.py
+++ b/tests/lib/test_constructor.py
@@ -3,25 +3,25 @@
 import pprint
 
 import datetime
-try:
-    set
-except NameError:
-    from sets import Set as set
 import yaml.tokens
 
+# Import any packages here that need to be referenced in .code files.
+import signal
+
 def execute(code):
-    exec code
+    global value
+    exec(code)
     return value
 
 def _make_objects():
     global MyLoader, MyDumper, MyTestClass1, MyTestClass2, MyTestClass3, YAMLObject1, YAMLObject2,  \
             AnObject, AnInstance, AState, ACustomState, InitArgs, InitArgsWithState,    \
-            NewArgs, NewArgsWithState, Reduce, ReduceWithState, MyInt, MyList, MyDict,  \
-            FixedOffset, today, execute
+            NewArgs, NewArgsWithState, Reduce, ReduceWithState, Slots, MyInt, MyList, MyDict,  \
+            FixedOffset, today, execute, MyFullLoader
 
-    class MyLoader(yaml.DangerLoader):
+    class MyLoader(yaml.Loader):
         pass
-    class MyDumper(yaml.DangerDumper):
+    class MyDumper(yaml.Dumper):
         pass
 
     class MyTestClass1:
@@ -41,7 +41,18 @@
     def represent1(representer, native):
         return representer.represent_mapping("!tag1", native.__dict__)
 
+    def my_time_constructor(constructor, node):
+        seq = constructor.construct_sequence(node)
+        dt = seq[0]
+        tz = None
+        try:
+            tz = dt.tzinfo.tzname(dt)
+        except:
+            pass
+        return [dt, tz]
+
     yaml.add_constructor("!tag1", construct1, Loader=MyLoader)
+    yaml.add_constructor("!MyTime", my_time_constructor, Loader=MyLoader)
     yaml.add_representer(MyTestClass1, represent1, Dumper=MyDumper)
 
     class MyTestClass2(MyTestClass1, yaml.YAMLObject):
@@ -103,7 +114,7 @@
             else:
                 return False
 
-    class AnObject(object):
+    class AnObject:
         def __new__(cls, foo=None, bar=None, baz=None):
             self = object.__new__(cls)
             self.foo = foo
@@ -147,20 +158,6 @@
         def __setstate__(self, state):
             self.foo, self.bar, self.baz = state
 
-    class InitArgs(AnInstance):
-        def __getinitargs__(self):
-            return (self.foo, self.bar, self.baz)
-        def __getstate__(self):
-            return {}
-
-    class InitArgsWithState(AnInstance):
-        def __getinitargs__(self):
-            return (self.foo, self.bar)
-        def __getstate__(self):
-            return self.baz
-        def __setstate__(self, state):
-            self.baz = state
-
     class NewArgs(AnObject):
         def __getnewargs__(self):
             return (self.foo, self.bar, self.baz)
@@ -175,6 +172,10 @@
         def __setstate__(self, state):
             self.baz = state
 
+    InitArgs = NewArgs
+
+    InitArgsWithState = NewArgsWithState
+
     class Reduce(AnObject):
         def __reduce__(self):
             return self.__class__, (self.foo, self.bar, self.baz)
@@ -185,6 +186,17 @@
         def __setstate__(self, state):
             self.baz = state
 
+    class Slots:
+        __slots__ = ("foo", "bar", "baz")
+        def __init__(self, foo=None, bar=None, baz=None):
+            self.foo = foo
+            self.bar = bar
+            self.baz = baz
+
+        def __eq__(self, other):
+            return type(self) is type(other) and \
+                (self.foo, self.bar, self.baz) == (other.foo, other.bar, other.baz)
+
     class MyInt(int):
         def __eq__(self, other):
             return type(self) is type(other) and int(self) == int(other)
@@ -213,6 +225,10 @@
         def dst(self, dt):
             return datetime.timedelta(0)
 
+    class MyFullLoader(yaml.FullLoader):
+        def get_state_keys_blacklist(self):
+            return super().get_state_keys_blacklist() + ['^mymethod$', '^wrong_.*$']
+
     today = datetime.date.today()
 
 def _load_code(expression):
@@ -231,8 +247,6 @@
         return '{%s}' % ', '.join(items)
     elif isinstance(data, datetime.datetime):
         return repr(data.utctimetuple())
-    elif isinstance(data, unicode):
-        return data.encode('utf-8')
     elif isinstance(data, float) and data != data:
         return '?'
     else:
@@ -243,32 +257,48 @@
     native1 = None
     native2 = None
     try:
-        native1 = list(yaml.load_all(open(data_filename, 'rb'), Loader=MyLoader))
+        with open(data_filename, 'rb') as file:
+            native1 = list(yaml.load_all(file, Loader=MyLoader))
         if len(native1) == 1:
             native1 = native1[0]
-        native2 = _load_code(open(code_filename, 'rb').read())
+        with open(code_filename, 'rb') as file:
+            native2 = _load_code(file.read())
         try:
             if native1 == native2:
                 return
         except TypeError:
             pass
         if verbose:
-            print "SERIALIZED NATIVE1:"
-            print _serialize_value(native1)
-            print "SERIALIZED NATIVE2:"
-            print _serialize_value(native2)
+            print("SERIALIZED NATIVE1:")
+            print(_serialize_value(native1))
+            print("SERIALIZED NATIVE2:")
+            print(_serialize_value(native2))
         assert _serialize_value(native1) == _serialize_value(native2), (native1, native2)
     finally:
         if verbose:
-            print "NATIVE1:"
+            print("NATIVE1:")
             pprint.pprint(native1)
-            print "NATIVE2:"
+            print("NATIVE2:")
             pprint.pprint(native2)
 
 test_constructor_types.unittest = ['.data', '.code']
 
+def test_subclass_blacklist_types(data_filename, verbose=False):
+    _make_objects()
+    try:
+        with open(data_filename, 'rb') as file:
+            yaml.load(file.read(), MyFullLoader)
+    except yaml.YAMLError as exc:
+        if verbose:
+            print("%s:" % exc.__class__.__name__, exc)
+    else:
+        raise AssertionError("expected an exception")
+
+test_subclass_blacklist_types.unittest = ['.subclass_blacklist']
+
 if __name__ == '__main__':
     import sys, test_constructor
     sys.modules['test_constructor'] = sys.modules['__main__']
     import test_appliance
     test_appliance.run(globals())
+
diff --git a/tests/lib/test_dump_load.py b/tests/lib/test_dump_load.py
new file mode 100644
index 0000000..f3b10b0
--- /dev/null
+++ b/tests/lib/test_dump_load.py
@@ -0,0 +1,23 @@
+import yaml
+
+def test_dump(verbose=False):
+    assert yaml.dump(['foo'])
+test_dump.unittest = True
+
+def test_load_no_loader(verbose=False):
+    try:
+        yaml.load("- foo\n")
+    except TypeError:
+        return True
+    assert(False, "load() require Loader=...")
+test_load_no_loader.unittest = True
+
+def test_load_safeloader(verbose=False):
+    assert yaml.load("- foo\n", Loader=yaml.SafeLoader)
+test_load_safeloader.unittest = True
+
+if __name__ == '__main__':
+    import sys, test_load
+    sys.modules['test_load'] = sys.modules['__main__']
+    import test_appliance
+    test_appliance.run(globals())
diff --git a/tests/lib/test_emitter.py b/tests/lib/test_emitter.py
index 61fd941..5eba0a3 100644
--- a/tests/lib/test_emitter.py
+++ b/tests/lib/test_emitter.py
@@ -15,23 +15,25 @@
             assert event1.value == event2.value, (event1, event2)
 
 def test_emitter_on_data(data_filename, canonical_filename, verbose=False):
-    events = list(yaml.parse(open(data_filename, 'rb')))
+    with open(data_filename, 'rb') as file:
+        events = list(yaml.parse(file))
     output = yaml.emit(events)
     if verbose:
-        print "OUTPUT:"
-        print output
+        print("OUTPUT:")
+        print(output)
     new_events = list(yaml.parse(output))
     _compare_events(events, new_events)
 
 test_emitter_on_data.unittest = ['.data', '.canonical']
 
 def test_emitter_on_canonical(canonical_filename, verbose=False):
-    events = list(yaml.parse(open(canonical_filename, 'rb')))
+    with open(canonical_filename, 'rb') as file:
+        events = list(yaml.parse(file))
     for canonical in [False, True]:
         output = yaml.emit(events, canonical=canonical)
         if verbose:
-            print "OUTPUT (canonical=%s):" % canonical
-            print output
+            print("OUTPUT (canonical=%s):" % canonical)
+            print(output)
         new_events = list(yaml.parse(output))
         _compare_events(events, new_events)
 
@@ -39,7 +41,8 @@
 
 def test_emitter_styles(data_filename, canonical_filename, verbose=False):
     for filename in [data_filename, canonical_filename]:
-        events = list(yaml.parse(open(filename, 'rb')))
+        with open(filename, 'rb') as file:
+            events = list(yaml.parse(file))
         for flow_style in [False, True]:
             for style in ['|', '>', '"', '\'', '']:
                 styled_events = []
@@ -56,8 +59,8 @@
                     styled_events.append(event)
                 output = yaml.emit(styled_events)
                 if verbose:
-                    print "OUTPUT (filename=%r, flow_style=%r, style=%r)" % (filename, flow_style, style)
-                    print output
+                    print("OUTPUT (filename=%r, flow_style=%r, style=%r)" % (filename, flow_style, style))
+                    print(output)
                 new_events = list(yaml.parse(output))
                 _compare_events(events, new_events)
 
@@ -86,11 +89,12 @@
 EventsLoader.add_constructor(None, EventsLoader.construct_event)
 
 def test_emitter_events(events_filename, verbose=False):
-    events = list(yaml.load(open(events_filename, 'rb'), Loader=EventsLoader))
+    with open(events_filename, 'rb') as file:
+        events = list(yaml.load(file, Loader=EventsLoader))
     output = yaml.emit(events)
     if verbose:
-        print "OUTPUT:"
-        print output
+        print("OUTPUT:")
+        print(output)
     new_events = list(yaml.parse(output))
     _compare_events(events, new_events)
 
diff --git a/tests/lib/test_errors.py b/tests/lib/test_errors.py
index 7dc9388..45f233f 100644
--- a/tests/lib/test_errors.py
+++ b/tests/lib/test_errors.py
@@ -3,10 +3,11 @@
 
 def test_loader_error(error_filename, verbose=False):
     try:
-        list(yaml.load_all(open(error_filename, 'rb')))
-    except yaml.YAMLError, exc:
+        with open(error_filename, 'rb') as file:
+            list(yaml.load_all(file, yaml.FullLoader))
+    except yaml.YAMLError as exc:
         if verbose:
-            print "%s:" % exc.__class__.__name__, exc
+            print("%s:" % exc.__class__.__name__, exc)
     else:
         raise AssertionError("expected an exception")
 
@@ -14,10 +15,11 @@
 
 def test_loader_error_string(error_filename, verbose=False):
     try:
-        list(yaml.load_all(open(error_filename, 'rb').read()))
-    except yaml.YAMLError, exc:
+        with open(error_filename, 'rb') as file:
+            list(yaml.load_all(file.read(), yaml.FullLoader))
+    except yaml.YAMLError as exc:
         if verbose:
-            print "%s:" % exc.__class__.__name__, exc
+            print("%s:" % exc.__class__.__name__, exc)
     else:
         raise AssertionError("expected an exception")
 
@@ -25,37 +27,39 @@
 
 def test_loader_error_single(error_filename, verbose=False):
     try:
-        yaml.load(open(error_filename, 'rb').read())
-    except yaml.YAMLError, exc:
+        with open(error_filename, 'rb') as file:
+            yaml.load(file.read(), yaml.FullLoader)
+    except yaml.YAMLError as exc:
         if verbose:
-            print "%s:" % exc.__class__.__name__, exc
+            print("%s:" % exc.__class__.__name__, exc)
     else:
         raise AssertionError("expected an exception")
 
 test_loader_error_single.unittest = ['.single-loader-error']
 
 def test_emitter_error(error_filename, verbose=False):
-    events = list(yaml.load(open(error_filename, 'rb'),
-                    Loader=test_emitter.EventsLoader))
+    with open(error_filename, 'rb') as file:
+        events = list(yaml.load(file, Loader=test_emitter.EventsLoader))
     try:
         yaml.emit(events)
-    except yaml.YAMLError, exc:
+    except yaml.YAMLError as exc:
         if verbose:
-            print "%s:" % exc.__class__.__name__, exc
+            print("%s:" % exc.__class__.__name__, exc)
     else:
         raise AssertionError("expected an exception")
 
 test_emitter_error.unittest = ['.emitter-error']
 
 def test_dumper_error(error_filename, verbose=False):
-    code = open(error_filename, 'rb').read()
+    with open(error_filename, 'rb') as file:
+        code = file.read()
     try:
         import yaml
-        from StringIO import StringIO
-        exec code
-    except yaml.YAMLError, exc:
+        from io import StringIO
+        exec(code)
+    except yaml.YAMLError as exc:
         if verbose:
-            print "%s:" % exc.__class__.__name__, exc
+            print("%s:" % exc.__class__.__name__, exc)
     else:
         raise AssertionError("expected an exception")
 
diff --git a/tests/lib/test_input_output.py b/tests/lib/test_input_output.py
index 3277a88..6d82c0d 100644
--- a/tests/lib/test_input_output.py
+++ b/tests/lib/test_input_output.py
@@ -1,110 +1,109 @@
 
 import yaml
-import codecs, StringIO, tempfile, os, os.path
-
-def _unicode_open(file, encoding, errors='strict'):
-    info = codecs.lookup(encoding)
-    if isinstance(info, tuple):
-        reader = info[2]
-        writer = info[3]
-    else:
-        reader = info.streamreader
-        writer = info.streamwriter
-    srw = codecs.StreamReaderWriter(file, reader, writer, errors)
-    srw.encoding = encoding
-    return srw
+import codecs, io, tempfile, os, os.path
 
 def test_unicode_input(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
+    with open(unicode_filename, 'rb') as file:
+        data = file.read().decode('utf-8')
     value = ' '.join(data.split())
-    output = yaml.load(_unicode_open(StringIO.StringIO(data.encode('utf-8')), 'utf-8'))
+    output = yaml.full_load(data)
     assert output == value, (output, value)
-    for input in [data, data.encode('utf-8'),
+    output = yaml.full_load(io.StringIO(data))
+    assert output == value, (output, value)
+    for input in [data.encode('utf-8'),
                     codecs.BOM_UTF8+data.encode('utf-8'),
                     codecs.BOM_UTF16_BE+data.encode('utf-16-be'),
                     codecs.BOM_UTF16_LE+data.encode('utf-16-le')]:
         if verbose:
-            print "INPUT:", repr(input[:10]), "..."
-        output = yaml.load(input)
+            print("INPUT:", repr(input[:10]), "...")
+        output = yaml.full_load(input)
         assert output == value, (output, value)
-        output = yaml.load(StringIO.StringIO(input))
+        output = yaml.full_load(io.BytesIO(input))
         assert output == value, (output, value)
 
 test_unicode_input.unittest = ['.unicode']
 
 def test_unicode_input_errors(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
+    with open(unicode_filename, 'rb') as file:
+        data = file.read().decode('utf-8')
     for input in [data.encode('utf-16-be'),
             data.encode('utf-16-le'),
             codecs.BOM_UTF8+data.encode('utf-16-be'),
             codecs.BOM_UTF8+data.encode('utf-16-le')]:
 
         try:
-            yaml.load(input)
-        except yaml.YAMLError, exc:
+            yaml.full_load(input)
+        except yaml.YAMLError as exc:
             if verbose:
-                print exc
+                print(exc)
         else:
             raise AssertionError("expected an exception")
         try:
-            yaml.load(StringIO.StringIO(input))
-        except yaml.YAMLError, exc:
+            yaml.full_load(io.BytesIO(input))
+        except yaml.YAMLError as exc:
             if verbose:
-                print exc
+                print(exc)
         else:
             raise AssertionError("expected an exception")
 
 test_unicode_input_errors.unittest = ['.unicode']
 
 def test_unicode_output(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
+    with open(unicode_filename, 'rb') as file:
+        data = file.read().decode('utf-8')
     value = ' '.join(data.split())
     for allow_unicode in [False, True]:
         data1 = yaml.dump(value, allow_unicode=allow_unicode)
         for encoding in [None, 'utf-8', 'utf-16-be', 'utf-16-le']:
-            stream = StringIO.StringIO()
-            yaml.dump(value, _unicode_open(stream, 'utf-8'), encoding=encoding, allow_unicode=allow_unicode)
+            stream = io.StringIO()
+            yaml.dump(value, stream, encoding=encoding, allow_unicode=allow_unicode)
             data2 = stream.getvalue()
             data3 = yaml.dump(value, encoding=encoding, allow_unicode=allow_unicode)
-            stream = StringIO.StringIO()
-            yaml.dump(value, stream, encoding=encoding, allow_unicode=allow_unicode)
-            data4 = stream.getvalue()
+            if encoding is not None:
+                assert isinstance(data3, bytes)
+                data3 = data3.decode(encoding)
+            stream = io.BytesIO()
+            if encoding is None:
+                try:
+                    yaml.dump(value, stream, encoding=encoding, allow_unicode=allow_unicode)
+                except TypeError as exc:
+                    if verbose:
+                        print(exc)
+                    data4 = None
+                else:
+                    raise AssertionError("expected an exception")
+            else:
+                yaml.dump(value, stream, encoding=encoding, allow_unicode=allow_unicode)
+                data4 = stream.getvalue()
+                if verbose:
+                    print("BYTES:", data4[:50])
+                data4 = data4.decode(encoding)
 
             assert isinstance(data1, str), (type(data1), encoding)
-            data1.decode('utf-8')
             assert isinstance(data2, str), (type(data2), encoding)
-            data2.decode('utf-8')
-            if encoding is None:
-                assert isinstance(data3, unicode), (type(data3), encoding)
-                assert isinstance(data4, unicode), (type(data4), encoding)
-            else:
-                assert isinstance(data3, str), (type(data3), encoding)
-                data3.decode(encoding)
-                assert isinstance(data4, str), (type(data4), encoding)
-                data4.decode(encoding)
 
 test_unicode_output.unittest = ['.unicode']
 
 def test_file_output(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
+    with open(unicode_filename, 'rb') as file:
+        data = file.read().decode('utf-8')
     handle, filename = tempfile.mkstemp()
     os.close(handle)
     try:
-        stream = StringIO.StringIO()
+        stream = io.StringIO()
         yaml.dump(data, stream, allow_unicode=True)
         data1 = stream.getvalue()
-        stream = open(filename, 'wb')
-        yaml.dump(data, stream, allow_unicode=True)
-        stream.close()
-        data2 = open(filename, 'rb').read()
-        stream = open(filename, 'wb')
+        stream = io.BytesIO()
         yaml.dump(data, stream, encoding='utf-16-le', allow_unicode=True)
-        stream.close()
-        data3 = open(filename, 'rb').read().decode('utf-16-le')[1:].encode('utf-8')
-        stream = _unicode_open(open(filename, 'wb'), 'utf-8')
-        yaml.dump(data, stream, allow_unicode=True)
-        stream.close()
-        data4 = open(filename, 'rb').read()
+        data2 = stream.getvalue().decode('utf-16-le')[1:]
+        with open(filename, 'w', encoding='utf-16-le') as stream:
+            yaml.dump(data, stream, allow_unicode=True)
+        with open(filename, 'r', encoding='utf-16-le') as file:
+            data3 = file.read()
+        with open(filename, 'wb') as stream:
+            yaml.dump(data, stream, encoding='utf-8', allow_unicode=True)
+        with open(filename, 'r', encoding='utf-8') as file:
+            data4 = file.read()
         assert data1 == data2, (data1, data2)
         assert data1 == data3, (data1, data3)
         assert data1 == data4, (data1, data4)
@@ -115,23 +114,25 @@
 test_file_output.unittest = ['.unicode']
 
 def test_unicode_transfer(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
+    with open(unicode_filename, 'rb') as file:
+        data = file.read().decode('utf-8')
     for encoding in [None, 'utf-8', 'utf-16-be', 'utf-16-le']:
         input = data
         if encoding is not None:
-            input = (u'\ufeff'+input).encode(encoding)
+            input = ('\ufeff'+input).encode(encoding)
         output1 = yaml.emit(yaml.parse(input), allow_unicode=True)
-        stream = StringIO.StringIO()
-        yaml.emit(yaml.parse(input), _unicode_open(stream, 'utf-8'),
-                            allow_unicode=True)
-        output2 = stream.getvalue()
         if encoding is None:
-            assert isinstance(output1, unicode), (type(output1), encoding)
+            stream = io.StringIO()
         else:
-            assert isinstance(output1, str), (type(output1), encoding)
-            output1.decode(encoding)
-        assert isinstance(output2, str), (type(output2), encoding)
-        output2.decode('utf-8')
+            stream = io.BytesIO()
+        yaml.emit(yaml.parse(input), stream, allow_unicode=True)
+        output2 = stream.getvalue()
+        assert isinstance(output1, str), (type(output1), encoding)
+        if encoding is None:
+            assert isinstance(output2, str), (type(output1), encoding)
+        else:
+            assert isinstance(output2, bytes), (type(output1), encoding)
+            output2.decode(encoding)
 
 test_unicode_transfer.unittest = ['.unicode']
 
diff --git a/tests/lib/test_mark.py b/tests/lib/test_mark.py
index f30a121..02d8411 100644
--- a/tests/lib/test_mark.py
+++ b/tests/lib/test_mark.py
@@ -2,7 +2,8 @@
 import yaml
 
 def test_marks(marks_filename, verbose=False):
-    inputs = open(marks_filename, 'rb').read().split('---\n')[1:]
+    with open(marks_filename, 'r') as file:
+        inputs = file.read().split('---\n')[1:]
     for input in inputs:
         index = 0
         line = 0
@@ -14,10 +15,10 @@
             else:
                 column += 1
             index += 1
-        mark = yaml.Mark(marks_filename, index, line, column, unicode(input), index)
+        mark = yaml.Mark(marks_filename, index, line, column, input, index)
         snippet = mark.get_snippet(indent=2, max_length=79)
         if verbose:
-            print snippet
+            print(snippet)
         assert isinstance(snippet, str), type(snippet)
         assert snippet.count('\n') == 1, snippet.count('\n')
         data, pointer = snippet.split('\n')
diff --git a/tests/lib/test_multi_constructor.py b/tests/lib/test_multi_constructor.py
new file mode 100644
index 0000000..dcff2ce
--- /dev/null
+++ b/tests/lib/test_multi_constructor.py
@@ -0,0 +1,65 @@
+import yaml
+import pprint
+import sys
+
+def _load_code(expression):
+    return eval(expression)
+
+def myconstructor1(constructor, tag, node):
+    seq = constructor.construct_sequence(node)
+    return {tag: seq }
+
+def myconstructor2(constructor, tag, node):
+    seq = constructor.construct_sequence(node)
+    string = ''
+    try:
+        i = tag.index('!') + 1
+    except:
+        try:
+            i = tag.rindex(':') + 1
+        except:
+            pass
+    if i >= 0:
+        tag = tag[i:]
+    return { tag: seq }
+
+class Multi1(yaml.FullLoader):
+    pass
+class Multi2(yaml.FullLoader):
+    pass
+
+def test_multi_constructor(input_filename, code_filename, verbose=False):
+    with open(input_filename, 'rb') as file:
+        input = file.read().decode('utf-8')
+    with open(code_filename, 'rb') as file:
+        native = _load_code(file.read())
+
+    # default multi constructor for ! and !! tags
+    Multi1.add_multi_constructor('!', myconstructor1)
+    Multi1.add_multi_constructor('tag:yaml.org,2002:', myconstructor1)
+
+    data = yaml.load(input, Loader=Multi1)
+    if verbose:
+        print('Multi1:')
+        print(data)
+        print(native)
+    assert(data == native)
+
+
+    # default multi constructor for all tags
+    Multi2.add_multi_constructor(None, myconstructor2)
+
+    data = yaml.load(input, Loader=Multi2)
+    if verbose:
+        print('Multi2:')
+        print(data)
+        print(native)
+    assert(data == native)
+
+
+test_multi_constructor.unittest = ['.multi', '.code']
+
+if __name__ == '__main__':
+    import test_appliance
+    test_appliance.run(globals())
+
diff --git a/tests/lib/test_reader.py b/tests/lib/test_reader.py
index 3576ae6..ec88746 100644
--- a/tests/lib/test_reader.py
+++ b/tests/lib/test_reader.py
@@ -1,31 +1,34 @@
 
 import yaml.reader
-import codecs
 
 def _run_reader(data, verbose):
     try:
         stream = yaml.reader.Reader(data)
-        while stream.peek() != u'\0':
+        while stream.peek() != '\0':
             stream.forward()
-    except yaml.reader.ReaderError, exc:
+    except yaml.reader.ReaderError as exc:
         if verbose:
-            print exc
+            print(exc)
     else:
         raise AssertionError("expected an exception")
 
 def test_stream_error(error_filename, verbose=False):
-    _run_reader(open(error_filename, 'rb'), verbose)
-    _run_reader(open(error_filename, 'rb').read(), verbose)
+    with open(error_filename, 'rb') as file:
+        _run_reader(file, verbose)
+    with open(error_filename, 'rb') as file:
+        _run_reader(file.read(), verbose)
     for encoding in ['utf-8', 'utf-16-le', 'utf-16-be']:
         try:
-            data = unicode(open(error_filename, 'rb').read(), encoding)
+            with open(error_filename, 'rb') as file:
+                data = file.read().decode(encoding)
             break
         except UnicodeDecodeError:
             pass
     else:
         return
     _run_reader(data, verbose)
-    _run_reader(codecs.open(error_filename, encoding=encoding), verbose)
+    with open(error_filename, encoding=encoding) as file:
+        _run_reader(file, verbose)
 
 test_stream_error.unittest = ['.stream-error']
 
diff --git a/tests/lib/test_recursive.py b/tests/lib/test_recursive.py
index c67c170..527b258 100644
--- a/tests/lib/test_recursive.py
+++ b/tests/lib/test_recursive.py
@@ -23,27 +23,30 @@
         self.foo, self.bar = state['attributes']
 
 def test_recursive(recursive_filename, verbose=False):
-    exec open(recursive_filename, 'rb').read()
-    value1 = value
+    context = globals().copy()
+    with open(recursive_filename, 'rb') as file:
+        exec(file.read(), context)
+    value1 = context['value']
     output1 = None
     value2 = None
     output2 = None
     try:
-        output1 = yaml.danger_dump(value1)
-        value2 = yaml.danger_load(output1)
-        output2 = yaml.danger_dump(value2)
+        output1 = yaml.dump(value1)
+        value2 = yaml.unsafe_load(output1)
+        output2 = yaml.dump(value2)
         assert output1 == output2, (output1, output2)
     finally:
         if verbose:
-            #print "VALUE1:", value1
-            #print "VALUE2:", value2
-            print "OUTPUT1:"
-            print output1
-            print "OUTPUT2:"
-            print output2
+            print("VALUE1:", value1)
+            print("VALUE2:", value2)
+            print("OUTPUT1:")
+            print(output1)
+            print("OUTPUT2:")
+            print(output2)
 
 test_recursive.unittest = ['.recursive']
 
 if __name__ == '__main__':
     import test_appliance
     test_appliance.run(globals())
+
diff --git a/tests/lib/test_representer.py b/tests/lib/test_representer.py
index a82a32a..f3095bf 100644
--- a/tests/lib/test_representer.py
+++ b/tests/lib/test_representer.py
@@ -7,7 +7,8 @@
     test_constructor._make_objects()
     for allow_unicode in [False, True]:
         for encoding in ['utf-8', 'utf-16-be', 'utf-16-le']:
-            native1 = test_constructor._load_code(open(code_filename, 'rb').read())
+            with open(code_filename, 'rb') as file:
+                native1 = test_constructor._load_code(file.read())
             native2 = None
             try:
                 output = yaml.dump(native1, Dumper=test_constructor.MyDumper,
@@ -21,19 +22,19 @@
                 value1 = test_constructor._serialize_value(native1)
                 value2 = test_constructor._serialize_value(native2)
                 if verbose:
-                    print "SERIALIZED NATIVE1:"
-                    print value1
-                    print "SERIALIZED NATIVE2:"
-                    print value2
+                    print("SERIALIZED NATIVE1:")
+                    print(value1)
+                    print("SERIALIZED NATIVE2:")
+                    print(value2)
                 assert value1 == value2, (native1, native2)
             finally:
                 if verbose:
-                    print "NATIVE1:"
+                    print("NATIVE1:")
                     pprint.pprint(native1)
-                    print "NATIVE2:"
+                    print("NATIVE2:")
                     pprint.pprint(native2)
-                    print "OUTPUT:"
-                    print output
+                    print("OUTPUT:")
+                    print(output)
 
 test_representer_types.unittest = ['.code']
 
diff --git a/tests/lib/test_resolver.py b/tests/lib/test_resolver.py
index 5566750..d893941 100644
--- a/tests/lib/test_resolver.py
+++ b/tests/lib/test_resolver.py
@@ -6,17 +6,19 @@
     correct_tag = None
     node = None
     try:
-        correct_tag = open(detect_filename, 'rb').read().strip()
-        node = yaml.compose(open(data_filename, 'rb'))
+        with open(detect_filename, 'r') as file:
+            correct_tag = file.read().strip()
+        with open(data_filename, 'rb') as file:
+            node = yaml.compose(file)
         assert isinstance(node, yaml.SequenceNode), node
         for scalar in node.value:
             assert isinstance(scalar, yaml.ScalarNode), scalar
             assert scalar.tag == correct_tag, (scalar.tag, correct_tag)
     finally:
         if verbose:
-            print "CORRECT TAG:", correct_tag
+            print("CORRECT TAG:", correct_tag)
             if hasattr(node, 'value'):
-                print "CHILDREN:"
+                print("CHILDREN:")
                 pprint.pprint(node.value)
 
 test_implicit_resolver.unittest = ['.data', '.detect']
@@ -29,15 +31,15 @@
     class MyDumper(yaml.Dumper):
         pass
 
-    yaml.add_path_resolver(u'!root', [],
+    yaml.add_path_resolver('!root', [],
             Loader=MyLoader, Dumper=MyDumper)
-    yaml.add_path_resolver(u'!root/scalar', [], str,
+    yaml.add_path_resolver('!root/scalar', [], str,
             Loader=MyLoader, Dumper=MyDumper)
-    yaml.add_path_resolver(u'!root/key11/key12/*', ['key11', 'key12'],
+    yaml.add_path_resolver('!root/key11/key12/*', ['key11', 'key12'],
             Loader=MyLoader, Dumper=MyDumper)
-    yaml.add_path_resolver(u'!root/key21/1/*', ['key21', 1],
+    yaml.add_path_resolver('!root/key21/1/*', ['key21', 1],
             Loader=MyLoader, Dumper=MyDumper)
-    yaml.add_path_resolver(u'!root/key31/*/*/key14/map', ['key31', None, None, 'key14'], dict,
+    yaml.add_path_resolver('!root/key31/*/*/key14/map', ['key31', None, None, 'key14'], dict,
             Loader=MyLoader, Dumper=MyDumper)
 
     return MyLoader, MyDumper
@@ -58,8 +60,10 @@
 
 def test_path_resolver_loader(data_filename, path_filename, verbose=False):
     _make_path_loader_and_dumper()
-    nodes1 = list(yaml.compose_all(open(data_filename, 'rb').read(), Loader=MyLoader))
-    nodes2 = list(yaml.compose_all(open(path_filename, 'rb').read()))
+    with open(data_filename, 'rb') as file:
+        nodes1 = list(yaml.compose_all(file.read(), Loader=MyLoader))
+    with open(path_filename, 'rb') as file:
+        nodes2 = list(yaml.compose_all(file.read()))
     try:
         for node1, node2 in zip(nodes1, nodes2):
             data1 = _convert_node(node1)
@@ -67,22 +71,24 @@
             assert data1 == data2, (data1, data2)
     finally:
         if verbose:
-            print yaml.serialize_all(nodes1)
+            print(yaml.serialize_all(nodes1))
 
 test_path_resolver_loader.unittest = ['.data', '.path']
 
 def test_path_resolver_dumper(data_filename, path_filename, verbose=False):
     _make_path_loader_and_dumper()
     for filename in [data_filename, path_filename]:
-        output = yaml.serialize_all(yaml.compose_all(open(filename, 'rb')), Dumper=MyDumper)
+        with open(filename, 'rb') as file:
+            output = yaml.serialize_all(yaml.compose_all(file), Dumper=MyDumper)
         if verbose:
-            print output
+            print(output)
         nodes1 = yaml.compose_all(output)
-        nodes2 = yaml.compose_all(open(data_filename, 'rb'))
-        for node1, node2 in zip(nodes1, nodes2):
-            data1 = _convert_node(node1)
-            data2 = _convert_node(node2)
-            assert data1 == data2, (data1, data2)
+        with open(data_filename, 'rb') as file:
+            nodes2 = yaml.compose_all(file)
+            for node1, node2 in zip(nodes1, nodes2):
+                data1 = _convert_node(node1)
+                data2 = _convert_node(node2)
+                assert data1 == data2, (data1, data2)
 
 test_path_resolver_dumper.unittest = ['.data', '.path']
 
diff --git a/tests/lib/test_schema.py b/tests/lib/test_schema.py
new file mode 100644
index 0000000..f3370ec
--- /dev/null
+++ b/tests/lib/test_schema.py
@@ -0,0 +1,152 @@
+import yaml
+import sys
+import pprint
+import math
+
+def check_bool(value, expected):
+    if expected == 'false()' and value is False:
+        return 1
+    if expected == 'true()' and value is True:
+        return 1
+    print(value)
+    print(expected)
+    return 0
+
+def check_int(value, expected):
+    if (int(expected) == value):
+        return 1
+    print(value)
+    print(expected)
+    return 0
+
+def check_float(value, expected):
+    if expected == 'inf()':
+        if value == math.inf:
+            return 1
+    elif expected == 'inf-neg()':
+        if value == -math.inf:
+            return 1
+    elif expected == 'nan()':
+        if math.isnan(value):
+            return 1
+    elif (float(expected) == value):
+        return 1
+    else:
+        print(value)
+        print(expected)
+        return 0
+
+def check_str(value, expected):
+    if value == expected:
+        return 1
+    print(value)
+    print(expected)
+    return 0
+
+
+def _fail(input, test):
+    print("Input: >>" + input + "<<")
+    print(test)
+
+# The tests/data/yaml11.schema file is copied from
+# https://github.com/perlpunk/yaml-test-schema/blob/master/data/schema-yaml11.yaml
+def test_implicit_resolver(data_filename, skip_filename, verbose=False):
+    types = {
+        'str':   [str,   check_str],
+        'int':   [int,   check_int],
+        'float': [float, check_float],
+        'inf':   [float, check_float],
+        'nan':   [float, check_float],
+        'bool':  [bool,  check_bool],
+    }
+    with open(skip_filename, 'rb') as file:
+        skipdata = yaml.load(file, Loader=yaml.SafeLoader)
+    skip_load = skipdata['load']
+    skip_dump = skipdata['dump']
+    if verbose:
+        print(skip_load)
+    with open(data_filename, 'rb') as file:
+        tests = yaml.load(file, Loader=yaml.SafeLoader)
+
+    i = 0
+    fail = 0
+    for i, (input, test) in enumerate(sorted(tests.items())):
+        if verbose:
+            print('-------------------- ' + str(i))
+
+        # Skip known loader bugs
+        if input in skip_load:
+            continue
+
+        exp_type = test[0]
+        data     = test[1]
+        exp_dump = test[2]
+
+        # Test loading
+        try:
+            loaded = yaml.safe_load(input)
+        except:
+            print("Error:", sys.exc_info()[0], '(', sys.exc_info()[1], ')')
+            fail+=1
+            _fail(input, test)
+            continue
+
+        if verbose:
+            print(input)
+            print(test)
+            print(loaded)
+            print(type(loaded))
+
+        if exp_type == 'null':
+            if loaded is None:
+                pass
+            else:
+                fail+=1
+                _fail(input, test)
+        else:
+            t = types[exp_type][0]
+            code = types[exp_type][1]
+            if isinstance(loaded, t):
+                if code(loaded, data):
+                    pass
+                else:
+                    fail+=1
+                    _fail(input, test)
+            else:
+                fail+=1
+                _fail(input, test)
+
+        # Skip known dumper bugs
+        if input in skip_dump:
+            continue
+
+        dump = yaml.safe_dump(loaded, explicit_end=False)
+        # strip trailing newlines and footers
+        if dump.endswith('\n...\n'):
+            dump = dump[:-5]
+        if dump.endswith('\n'):
+            dump = dump[:-1]
+        if dump == exp_dump:
+            pass
+        else:
+            print("Compare: >>" + dump + "<< >>" + exp_dump + "<<")
+            fail+=1
+            _fail(input, test)
+
+#        if i >= 80:
+#            break
+
+    if fail > 0:
+        print("Failed " + str(fail) + " / " + str(i) + " tests")
+        assert(False)
+    else:
+        print("Passed " + str(i) + " tests")
+    print("Skipped " + str(len(skip_load)) + " load tests")
+    print("Skipped " + str(len(skip_dump)) + " dump tests")
+
+test_implicit_resolver.unittest = ['.schema', '.schema-skip']
+
+if __name__ == '__main__':
+    import test_appliance
+    test_appliance.run(globals())
+
diff --git a/tests/lib/test_sort_keys.py b/tests/lib/test_sort_keys.py
new file mode 100644
index 0000000..d9de8e6
--- /dev/null
+++ b/tests/lib/test_sort_keys.py
@@ -0,0 +1,31 @@
+import yaml
+import pprint
+import sys
+
+def test_sort_keys(input_filename, sorted_filename, verbose=False):
+    with open(input_filename, 'rb') as file:
+        input = file.read().decode('utf-8')
+    with open(sorted_filename, 'rb') as file:
+        sorted = file.read().decode('utf-8')
+    data = yaml.load(input, Loader=yaml.FullLoader)
+    dump_sorted = yaml.dump(data, default_flow_style=False, sort_keys=True)
+    dump_unsorted = yaml.dump(data, default_flow_style=False, sort_keys=False)
+    dump_unsorted_safe = yaml.dump(data, default_flow_style=False, sort_keys=False, Dumper=yaml.SafeDumper)
+    if verbose:
+        print("INPUT:")
+        print(input)
+        print("DATA:")
+        print(data)
+
+    assert dump_sorted == sorted
+
+    if sys.version_info>=(3,7):
+        assert dump_unsorted == input
+        assert dump_unsorted_safe == input
+
+test_sort_keys.unittest = ['.sort', '.sorted']
+
+if __name__ == '__main__':
+    import test_appliance
+    test_appliance.run(globals())
+
diff --git a/tests/lib/test_structure.py b/tests/lib/test_structure.py
index 61bcb80..cbd4c3e 100644
--- a/tests/lib/test_structure.py
+++ b/tests/lib/test_structure.py
@@ -34,23 +34,27 @@
 
 def test_structure(data_filename, structure_filename, verbose=False):
     nodes1 = []
-    nodes2 = eval(open(structure_filename, 'rb').read())
+    with open(structure_filename, 'r') as file:
+        nodes2 = eval(file.read())
     try:
-        loader = yaml.Loader(open(data_filename, 'rb'))
-        while loader.check_event():
-            if loader.check_event(yaml.StreamStartEvent, yaml.StreamEndEvent,
-                                yaml.DocumentStartEvent, yaml.DocumentEndEvent):
-                loader.get_event()
-                continue
-            nodes1.append(_convert_structure(loader))
+        with open(data_filename, 'rb') as file:
+            loader = yaml.Loader(file)
+            while loader.check_event():
+                if loader.check_event(
+                    yaml.StreamStartEvent, yaml.StreamEndEvent,
+                    yaml.DocumentStartEvent, yaml.DocumentEndEvent
+                ):
+                    loader.get_event()
+                    continue
+                nodes1.append(_convert_structure(loader))
         if len(nodes1) == 1:
             nodes1 = nodes1[0]
         assert nodes1 == nodes2, (nodes1, nodes2)
     finally:
         if verbose:
-            print "NODES1:"
+            print("NODES1:")
             pprint.pprint(nodes1)
-            print "NODES2:"
+            print("NODES2:")
             pprint.pprint(nodes2)
 
 test_structure.unittest = ['.data', '.structure']
@@ -62,7 +66,7 @@
         if isinstance(event1, yaml.AliasEvent) and full:
             assert event1.anchor == event2.anchor, (event1, event2)
         if isinstance(event1, (yaml.ScalarEvent, yaml.CollectionStartEvent)):
-            if (event1.tag not in [None, u'!'] and event2.tag not in [None, u'!']) or full:
+            if (event1.tag not in [None, '!'] and event2.tag not in [None, '!']) or full:
                 assert event1.tag == event2.tag, (event1, event2)
         if isinstance(event1, yaml.ScalarEvent):
             assert event1.value == event2.value, (event1, event2)
@@ -71,14 +75,16 @@
     events1 = None
     events2 = None
     try:
-        events1 = list(yaml.parse(open(data_filename, 'rb')))
-        events2 = list(yaml.canonical_parse(open(canonical_filename, 'rb')))
+        with open(data_filename, 'rb') as file:
+            events1 = list(yaml.parse(file))
+        with open(canonical_filename, 'rb') as file:
+            events2 = list(yaml.canonical_parse(file))
         _compare_events(events1, events2)
     finally:
         if verbose:
-            print "EVENTS1:"
+            print("EVENTS1:")
             pprint.pprint(events1)
-            print "EVENTS2:"
+            print("EVENTS2:")
             pprint.pprint(events2)
 
 test_parser.unittest = ['.data', '.canonical']
@@ -87,14 +93,16 @@
     events1 = None
     events2 = None
     try:
-        events1 = list(yaml.parse(open(canonical_filename, 'rb')))
-        events2 = list(yaml.canonical_parse(open(canonical_filename, 'rb')))
+        with open(canonical_filename, 'rb') as file:
+            events1 = list(yaml.parse(file))
+        with open(canonical_filename, 'rb') as file:
+            events2 = list(yaml.canonical_parse(file))
         _compare_events(events1, events2, full=True)
     finally:
         if verbose:
-            print "EVENTS1:"
+            print("EVENTS1:")
             pprint.pprint(events1)
-            print "EVENTS2:"
+            print("EVENTS2:")
             pprint.pprint(events2)
 
 test_parser_on_canonical.unittest = ['.canonical']
@@ -117,16 +125,18 @@
     nodes1 = None
     nodes2 = None
     try:
-        nodes1 = list(yaml.compose_all(open(data_filename, 'rb')))
-        nodes2 = list(yaml.canonical_compose_all(open(canonical_filename, 'rb')))
+        with open(data_filename, 'rb') as file:
+            nodes1 = list(yaml.compose_all(file))
+        with open(canonical_filename, 'rb') as file:
+            nodes2 = list(yaml.canonical_compose_all(file))
         assert len(nodes1) == len(nodes2), (len(nodes1), len(nodes2))
         for node1, node2 in zip(nodes1, nodes2):
             _compare_nodes(node1, node2)
     finally:
         if verbose:
-            print "NODES1:"
+            print("NODES1:")
             pprint.pprint(nodes1)
-            print "NODES2:"
+            print("NODES2:")
             pprint.pprint(nodes2)
 
 test_composer.unittest = ['.data', '.canonical']
@@ -139,12 +149,12 @@
             return tuple(yaml.Loader.construct_sequence(self, node))
         def construct_mapping(self, node):
             pairs = self.construct_pairs(node)
-            pairs.sort()
+            pairs.sort(key=(lambda i: str(i)))
             return pairs
         def construct_undefined(self, node):
             return self.construct_scalar(node)
 
-    MyLoader.add_constructor(u'tag:yaml.org,2002:map', MyLoader.construct_mapping)
+    MyLoader.add_constructor('tag:yaml.org,2002:map', MyLoader.construct_mapping)
     MyLoader.add_constructor(None, MyLoader.construct_undefined)
 
 def _make_canonical_loader():
@@ -155,12 +165,12 @@
             return tuple(yaml.CanonicalLoader.construct_sequence(self, node))
         def construct_mapping(self, node):
             pairs = self.construct_pairs(node)
-            pairs.sort()
+            pairs.sort(key=(lambda i: str(i)))
             return pairs
         def construct_undefined(self, node):
             return self.construct_scalar(node)
 
-    MyCanonicalLoader.add_constructor(u'tag:yaml.org,2002:map', MyCanonicalLoader.construct_mapping)
+    MyCanonicalLoader.add_constructor('tag:yaml.org,2002:map', MyCanonicalLoader.construct_mapping)
     MyCanonicalLoader.add_constructor(None, MyCanonicalLoader.construct_undefined)
 
 def test_constructor(data_filename, canonical_filename, verbose=False):
@@ -169,14 +179,16 @@
     native1 = None
     native2 = None
     try:
-        native1 = list(yaml.load_all(open(data_filename, 'rb'), Loader=MyLoader))
-        native2 = list(yaml.load_all(open(canonical_filename, 'rb'), Loader=MyCanonicalLoader))
+        with open(data_filename, 'rb') as file:
+            native1 = list(yaml.load_all(file, Loader=MyLoader))
+        with open(canonical_filename, 'rb') as file:
+            native2 = list(yaml.load_all(file, Loader=MyCanonicalLoader))
         assert native1 == native2, (native1, native2)
     finally:
         if verbose:
-            print "NATIVE1:"
+            print("NATIVE1:")
             pprint.pprint(native1)
-            print "NATIVE2:"
+            print("NATIVE2:")
             pprint.pprint(native2)
 
 test_constructor.unittest = ['.data', '.canonical']
diff --git a/tests/lib/test_tokens.py b/tests/lib/test_tokens.py
index 9613fa0..89ce7ac 100644
--- a/tests/lib/test_tokens.py
+++ b/tests/lib/test_tokens.py
@@ -44,15 +44,17 @@
 
 def test_tokens(data_filename, tokens_filename, verbose=False):
     tokens1 = []
-    tokens2 = open(tokens_filename, 'rb').read().split()
+    with open(tokens_filename, 'r') as file:
+        tokens2 = file.read().split()
     try:
-        for token in yaml.scan(open(data_filename, 'rb')):
-            if not isinstance(token, (yaml.StreamStartToken, yaml.StreamEndToken)):
-                tokens1.append(_replaces[token.__class__])
+        with open(data_filename, 'rb') as file:
+            for token in yaml.scan(file):
+                if not isinstance(token, (yaml.StreamStartToken, yaml.StreamEndToken)):
+                    tokens1.append(_replaces[token.__class__])
     finally:
         if verbose:
-            print "TOKENS1:", ' '.join(tokens1)
-            print "TOKENS2:", ' '.join(tokens2)
+            print("TOKENS1:", ' '.join(tokens1))
+            print("TOKENS2:", ' '.join(tokens2))
     assert len(tokens1) == len(tokens2), (tokens1, tokens2)
     for token1, token2 in zip(tokens1, tokens2):
         assert token1 == token2, (token1, token2)
@@ -63,8 +65,9 @@
     for filename in [data_filename, canonical_filename]:
         tokens = []
         try:
-            for token in yaml.scan(open(filename, 'rb')):
-                tokens.append(token.__class__.__name__)
+            with open(filename, 'rb') as file:
+                for token in yaml.scan(file):
+                    tokens.append(token.__class__.__name__)
         finally:
             if verbose:
                 pprint.pprint(tokens)
diff --git a/tests/lib/test_yaml.py b/tests/lib/test_yaml.py
index 0927368..a5c10a3 100644
--- a/tests/lib/test_yaml.py
+++ b/tests/lib/test_yaml.py
@@ -1,4 +1,5 @@
 
+from test_dump_load import *
 from test_mark import *
 from test_reader import *
 from test_canonical import *
@@ -11,6 +12,10 @@
 from test_representer import *
 from test_recursive import *
 from test_input_output import *
+from test_sort_keys import *
+from test_multi_constructor import *
+
+from test_schema import *
 
 if __name__ == '__main__':
     import test_appliance
diff --git a/tests/lib/test_yaml_ext.py b/tests/lib/test_yaml_ext.py
index bdfda3e..e1c4bb8 100644
--- a/tests/lib/test_yaml_ext.py
+++ b/tests/lib/test_yaml_ext.py
@@ -1,6 +1,6 @@
 
-import _yaml, yaml
-import types, pprint
+import yaml._yaml, yaml
+import types, pprint, tempfile, sys, os
 
 yaml.PyBaseLoader = yaml.BaseLoader
 yaml.PySafeLoader = yaml.SafeLoader
@@ -117,10 +117,15 @@
 
 def test_c_version(verbose=False):
     if verbose:
-        print _yaml.get_version()
-        print _yaml.get_version_string()
-    assert ("%s.%s.%s" % _yaml.get_version()) == _yaml.get_version_string(),    \
-            (_yaml.get_version(), _yaml.get_version_string())
+        print(_yaml.get_version())
+        print(_yaml.get_version_string())
+    assert ("%s.%s.%s" % yaml._yaml.get_version()) == yaml._yaml.get_version_string(),    \
+            (_yaml.get_version(), yaml._yaml.get_version_string())
+
+def test_deprecate_yaml_module():
+    import _yaml
+    assert _yaml.__package__ == ''
+    assert isinstance(_yaml.get_version(), str)
 
 def _compare_scanners(py_data, c_data, verbose):
     py_tokens = list(yaml.scan(py_data, Loader=yaml.PyLoader))
@@ -143,20 +148,20 @@
             assert py_end == c_end, (py_end, c_end)
     finally:
         if verbose:
-            print "PY_TOKENS:"
+            print("PY_TOKENS:")
             pprint.pprint(py_tokens)
-            print "C_TOKENS:"
+            print("C_TOKENS:")
             pprint.pprint(c_tokens)
 
 def test_c_scanner(data_filename, canonical_filename, verbose=False):
-    _compare_scanners(open(data_filename, 'rb'),
-            open(data_filename, 'rb'), verbose)
-    _compare_scanners(open(data_filename, 'rb').read(),
-            open(data_filename, 'rb').read(), verbose)
-    _compare_scanners(open(canonical_filename, 'rb'),
-            open(canonical_filename, 'rb'), verbose)
-    _compare_scanners(open(canonical_filename, 'rb').read(),
-            open(canonical_filename, 'rb').read(), verbose)
+    with open(data_filename, 'rb') as file1, open(data_filename, 'rb') as file2:
+        _compare_scanners(file1, file2, verbose)
+    with open(data_filename, 'rb') as file1, open(data_filename, 'rb') as file2:
+        _compare_scanners(file1.read(), file2.read(), verbose)
+    with open(canonical_filename, 'rb') as file1, open(canonical_filename, 'rb') as file2:
+        _compare_scanners(file1, file2, verbose)
+    with open(canonical_filename, 'rb') as file1, open(canonical_filename, 'rb') as file2:
+        _compare_scanners(file1.read(), file2.read(), verbose)
 
 test_c_scanner.unittest = ['.data', '.canonical']
 test_c_scanner.skip = ['.skip-ext']
@@ -176,20 +181,20 @@
                 assert py_value == c_value, (py_event, c_event, attribute)
     finally:
         if verbose:
-            print "PY_EVENTS:"
+            print("PY_EVENTS:")
             pprint.pprint(py_events)
-            print "C_EVENTS:"
+            print("C_EVENTS:")
             pprint.pprint(c_events)
 
 def test_c_parser(data_filename, canonical_filename, verbose=False):
-    _compare_parsers(open(data_filename, 'rb'),
-            open(data_filename, 'rb'), verbose)
-    _compare_parsers(open(data_filename, 'rb').read(),
-            open(data_filename, 'rb').read(), verbose)
-    _compare_parsers(open(canonical_filename, 'rb'),
-            open(canonical_filename, 'rb'), verbose)
-    _compare_parsers(open(canonical_filename, 'rb').read(),
-            open(canonical_filename, 'rb').read(), verbose)
+    with open(data_filename, 'rb') as file1, open(data_filename, 'rb') as file2:
+        _compare_parsers(file1, file2, verbose)
+    with open(data_filename, 'rb') as file1, open(data_filename, 'rb') as file2:
+        _compare_parsers(file1.read(), file2.read(), verbose)
+    with open(canonical_filename, 'rb') as file1, open(canonical_filename, 'rb') as file2:
+        _compare_parsers(file1, file2, verbose)
+    with open(canonical_filename, 'rb') as file1, open(canonical_filename, 'rb') as file2:
+        _compare_parsers(file1.read(), file2.read(), verbose)
 
 test_c_parser.unittest = ['.data', '.canonical']
 test_c_parser.skip = ['.skip-ext']
@@ -198,7 +203,7 @@
     events = list(yaml.parse(data, Loader=yaml.PyLoader))
     c_data = yaml.emit(events, Dumper=yaml.CDumper)
     if verbose:
-        print c_data
+        print(c_data)
     py_events = list(yaml.parse(c_data, Loader=yaml.PyLoader))
     c_events = list(yaml.parse(c_data, Loader=yaml.CLoader))
     try:
@@ -210,8 +215,8 @@
                 value = getattr(event, attribute, None)
                 py_value = getattr(py_event, attribute, None)
                 c_value = getattr(c_event, attribute, None)
-                if attribute == 'tag' and value in [None, u'!'] \
-                        and py_value in [None, u'!'] and c_value in [None, u'!']:
+                if attribute == 'tag' and value in [None, '!'] \
+                        and py_value in [None, '!'] and c_value in [None, '!']:
                     continue
                 if attribute == 'explicit' and (py_value or c_value):
                     continue
@@ -219,20 +224,38 @@
                 assert value == c_value, (event, c_event, attribute)
     finally:
         if verbose:
-            print "EVENTS:"
+            print("EVENTS:")
             pprint.pprint(events)
-            print "PY_EVENTS:"
+            print("PY_EVENTS:")
             pprint.pprint(py_events)
-            print "C_EVENTS:"
+            print("C_EVENTS:")
             pprint.pprint(c_events)
 
 def test_c_emitter(data_filename, canonical_filename, verbose=False):
-    _compare_emitters(open(data_filename, 'rb').read(), verbose)
-    _compare_emitters(open(canonical_filename, 'rb').read(), verbose)
+    with open(data_filename, 'rb') as file:
+        _compare_emitters(file.read(), verbose)
+    with open(canonical_filename, 'rb') as file:
+        _compare_emitters(file.read(), verbose)
 
 test_c_emitter.unittest = ['.data', '.canonical']
 test_c_emitter.skip = ['.skip-ext']
 
+def test_large_file(verbose=False):
+    SIZE_LINE = 24
+    SIZE_ITERATION = 0
+    SIZE_FILE = 31
+    if sys.maxsize <= 2**32:
+        return
+    if os.environ.get('PYYAML_TEST_GROUP', '') != 'all':
+        return
+    with tempfile.TemporaryFile() as temp_file:
+        for i in range(2**(SIZE_FILE-SIZE_ITERATION-SIZE_LINE) + 1):
+            temp_file.write(bytes(('-' + (' ' * (2**SIZE_LINE-4))+ '{}\n')*(2**SIZE_ITERATION), 'utf-8'))
+        temp_file.seek(0)
+        yaml.load(temp_file, Loader=yaml.CLoader)
+
+test_large_file.unittest = None
+
 def wrap_ext_function(function):
     def wrapper(*args, **kwds):
         _set_up()
@@ -240,11 +263,7 @@
             function(*args, **kwds)
         finally:
             _tear_down()
-    try:
-        wrapper.func_name = '%s_ext' % function.func_name
-    except TypeError:
-        pass
-    wrapper.unittest_name = '%s_ext' % function.func_name
+    wrapper.__name__ = '%s_ext' % function.__name__
     wrapper.unittest = function.unittest
     wrapper.skip = getattr(function, 'skip', [])+['.skip-ext']
     return wrapper
@@ -256,15 +275,13 @@
     for collection in collections:
         if not isinstance(collection, dict):
             collection = vars(collection)
-        keys = collection.keys()
-        keys.sort()
-        for key in keys:
+        for key in sorted(collection):
             value = collection[key]
             if isinstance(value, types.FunctionType) and hasattr(value, 'unittest'):
                 functions.append(wrap_ext_function(value))
     for function in functions:
-        assert function.unittest_name not in globals()
-        globals()[function.unittest_name] = function
+        assert function.__name__ not in globals()
+        globals()[function.__name__] = function
 
 import test_tokens, test_structure, test_errors, test_resolver, test_constructor,   \
         test_emitter, test_representer, test_recursive, test_input_output
diff --git a/tests/lib3/canonical.py b/tests/lib3/canonical.py
deleted file mode 100644
index a8b4e3a..0000000
--- a/tests/lib3/canonical.py
+++ /dev/null
@@ -1,361 +0,0 @@
-
-import yaml, yaml.composer, yaml.constructor, yaml.resolver
-
-class CanonicalError(yaml.YAMLError):
-    pass
-
-class CanonicalScanner:
-
-    def __init__(self, data):
-        if isinstance(data, bytes):
-            try:
-                data = data.decode('utf-8')
-            except UnicodeDecodeError:
-                raise CanonicalError("utf-8 stream is expected")
-        self.data = data+'\0'
-        self.index = 0
-        self.tokens = []
-        self.scanned = False
-
-    def check_token(self, *choices):
-        if not self.scanned:
-            self.scan()
-        if self.tokens:
-            if not choices:
-                return True
-            for choice in choices:
-                if isinstance(self.tokens[0], choice):
-                    return True
-        return False
-
-    def peek_token(self):
-        if not self.scanned:
-            self.scan()
-        if self.tokens:
-            return self.tokens[0]
-
-    def get_token(self, choice=None):
-        if not self.scanned:
-            self.scan()
-        token = self.tokens.pop(0)
-        if choice and not isinstance(token, choice):
-            raise CanonicalError("unexpected token "+repr(token))
-        return token
-
-    def get_token_value(self):
-        token = self.get_token()
-        return token.value
-
-    def scan(self):
-        self.tokens.append(yaml.StreamStartToken(None, None))
-        while True:
-            self.find_token()
-            ch = self.data[self.index]
-            if ch == '\0':
-                self.tokens.append(yaml.StreamEndToken(None, None))
-                break
-            elif ch == '%':
-                self.tokens.append(self.scan_directive())
-            elif ch == '-' and self.data[self.index:self.index+3] == '---':
-                self.index += 3
-                self.tokens.append(yaml.DocumentStartToken(None, None))
-            elif ch == '[':
-                self.index += 1
-                self.tokens.append(yaml.FlowSequenceStartToken(None, None))
-            elif ch == '{':
-                self.index += 1
-                self.tokens.append(yaml.FlowMappingStartToken(None, None))
-            elif ch == ']':
-                self.index += 1
-                self.tokens.append(yaml.FlowSequenceEndToken(None, None))
-            elif ch == '}':
-                self.index += 1
-                self.tokens.append(yaml.FlowMappingEndToken(None, None))
-            elif ch == '?':
-                self.index += 1
-                self.tokens.append(yaml.KeyToken(None, None))
-            elif ch == ':':
-                self.index += 1
-                self.tokens.append(yaml.ValueToken(None, None))
-            elif ch == ',':
-                self.index += 1
-                self.tokens.append(yaml.FlowEntryToken(None, None))
-            elif ch == '*' or ch == '&':
-                self.tokens.append(self.scan_alias())
-            elif ch == '!':
-                self.tokens.append(self.scan_tag())
-            elif ch == '"':
-                self.tokens.append(self.scan_scalar())
-            else:
-                raise CanonicalError("invalid token")
-        self.scanned = True
-
-    DIRECTIVE = '%YAML 1.1'
-
-    def scan_directive(self):
-        if self.data[self.index:self.index+len(self.DIRECTIVE)] == self.DIRECTIVE and \
-                self.data[self.index+len(self.DIRECTIVE)] in ' \n\0':
-            self.index += len(self.DIRECTIVE)
-            return yaml.DirectiveToken('YAML', (1, 1), None, None)
-        else:
-            raise CanonicalError("invalid directive")
-
-    def scan_alias(self):
-        if self.data[self.index] == '*':
-            TokenClass = yaml.AliasToken
-        else:
-            TokenClass = yaml.AnchorToken
-        self.index += 1
-        start = self.index
-        while self.data[self.index] not in ', \n\0':
-            self.index += 1
-        value = self.data[start:self.index]
-        return TokenClass(value, None, None)
-
-    def scan_tag(self):
-        self.index += 1
-        start = self.index
-        while self.data[self.index] not in ' \n\0':
-            self.index += 1
-        value = self.data[start:self.index]
-        if not value:
-            value = '!'
-        elif value[0] == '!':
-            value = 'tag:yaml.org,2002:'+value[1:]
-        elif value[0] == '<' and value[-1] == '>':
-            value = value[1:-1]
-        else:
-            value = '!'+value
-        return yaml.TagToken(value, None, None)
-
-    QUOTE_CODES = {
-        'x': 2,
-        'u': 4,
-        'U': 8,
-    }
-
-    QUOTE_REPLACES = {
-        '\\': '\\',
-        '\"': '\"',
-        ' ': ' ',
-        'a': '\x07',
-        'b': '\x08',
-        'e': '\x1B',
-        'f': '\x0C',
-        'n': '\x0A',
-        'r': '\x0D',
-        't': '\x09',
-        'v': '\x0B',
-        'N': '\u0085',
-        'L': '\u2028',
-        'P': '\u2029',
-        '_': '_',
-        '0': '\x00',
-    }
-
-    def scan_scalar(self):
-        self.index += 1
-        chunks = []
-        start = self.index
-        ignore_spaces = False
-        while self.data[self.index] != '"':
-            if self.data[self.index] == '\\':
-                ignore_spaces = False
-                chunks.append(self.data[start:self.index])
-                self.index += 1
-                ch = self.data[self.index]
-                self.index += 1
-                if ch == '\n':
-                    ignore_spaces = True
-                elif ch in self.QUOTE_CODES:
-                    length = self.QUOTE_CODES[ch]
-                    code = int(self.data[self.index:self.index+length], 16)
-                    chunks.append(chr(code))
-                    self.index += length
-                else:
-                    if ch not in self.QUOTE_REPLACES:
-                        raise CanonicalError("invalid escape code")
-                    chunks.append(self.QUOTE_REPLACES[ch])
-                start = self.index
-            elif self.data[self.index] == '\n':
-                chunks.append(self.data[start:self.index])
-                chunks.append(' ')
-                self.index += 1
-                start = self.index
-                ignore_spaces = True
-            elif ignore_spaces and self.data[self.index] == ' ':
-                self.index += 1
-                start = self.index
-            else:
-                ignore_spaces = False
-                self.index += 1
-        chunks.append(self.data[start:self.index])
-        self.index += 1
-        return yaml.ScalarToken(''.join(chunks), False, None, None)
-
-    def find_token(self):
-        found = False
-        while not found:
-            while self.data[self.index] in ' \t':
-                self.index += 1
-            if self.data[self.index] == '#':
-                while self.data[self.index] != '\n':
-                    self.index += 1
-            if self.data[self.index] == '\n':
-                self.index += 1
-            else:
-                found = True
-
-class CanonicalParser:
-
-    def __init__(self):
-        self.events = []
-        self.parsed = False
-
-    def dispose(self):
-        pass
-
-    # stream: STREAM-START document* STREAM-END
-    def parse_stream(self):
-        self.get_token(yaml.StreamStartToken)
-        self.events.append(yaml.StreamStartEvent(None, None))
-        while not self.check_token(yaml.StreamEndToken):
-            if self.check_token(yaml.DirectiveToken, yaml.DocumentStartToken):
-                self.parse_document()
-            else:
-                raise CanonicalError("document is expected, got "+repr(self.tokens[0]))
-        self.get_token(yaml.StreamEndToken)
-        self.events.append(yaml.StreamEndEvent(None, None))
-
-    # document: DIRECTIVE? DOCUMENT-START node
-    def parse_document(self):
-        node = None
-        if self.check_token(yaml.DirectiveToken):
-            self.get_token(yaml.DirectiveToken)
-        self.get_token(yaml.DocumentStartToken)
-        self.events.append(yaml.DocumentStartEvent(None, None))
-        self.parse_node()
-        self.events.append(yaml.DocumentEndEvent(None, None))
-
-    # node: ALIAS | ANCHOR? TAG? (SCALAR|sequence|mapping)
-    def parse_node(self):
-        if self.check_token(yaml.AliasToken):
-            self.events.append(yaml.AliasEvent(self.get_token_value(), None, None))
-        else:
-            anchor = None
-            if self.check_token(yaml.AnchorToken):
-                anchor = self.get_token_value()
-            tag = None
-            if self.check_token(yaml.TagToken):
-                tag = self.get_token_value()
-            if self.check_token(yaml.ScalarToken):
-                self.events.append(yaml.ScalarEvent(anchor, tag, (False, False), self.get_token_value(), None, None))
-            elif self.check_token(yaml.FlowSequenceStartToken):
-                self.events.append(yaml.SequenceStartEvent(anchor, tag, None, None))
-                self.parse_sequence()
-            elif self.check_token(yaml.FlowMappingStartToken):
-                self.events.append(yaml.MappingStartEvent(anchor, tag, None, None))
-                self.parse_mapping()
-            else:
-                raise CanonicalError("SCALAR, '[', or '{' is expected, got "+repr(self.tokens[0]))
-
-    # sequence: SEQUENCE-START (node (ENTRY node)*)? ENTRY? SEQUENCE-END
-    def parse_sequence(self):
-        self.get_token(yaml.FlowSequenceStartToken)
-        if not self.check_token(yaml.FlowSequenceEndToken):
-            self.parse_node()
-            while not self.check_token(yaml.FlowSequenceEndToken):
-                self.get_token(yaml.FlowEntryToken)
-                if not self.check_token(yaml.FlowSequenceEndToken):
-                    self.parse_node()
-        self.get_token(yaml.FlowSequenceEndToken)
-        self.events.append(yaml.SequenceEndEvent(None, None))
-
-    # mapping: MAPPING-START (map_entry (ENTRY map_entry)*)? ENTRY? MAPPING-END
-    def parse_mapping(self):
-        self.get_token(yaml.FlowMappingStartToken)
-        if not self.check_token(yaml.FlowMappingEndToken):
-            self.parse_map_entry()
-            while not self.check_token(yaml.FlowMappingEndToken):
-                self.get_token(yaml.FlowEntryToken)
-                if not self.check_token(yaml.FlowMappingEndToken):
-                    self.parse_map_entry()
-        self.get_token(yaml.FlowMappingEndToken)
-        self.events.append(yaml.MappingEndEvent(None, None))
-
-    # map_entry: KEY node VALUE node
-    def parse_map_entry(self):
-        self.get_token(yaml.KeyToken)
-        self.parse_node()
-        self.get_token(yaml.ValueToken)
-        self.parse_node()
-
-    def parse(self):
-        self.parse_stream()
-        self.parsed = True
-
-    def get_event(self):
-        if not self.parsed:
-            self.parse()
-        return self.events.pop(0)
-
-    def check_event(self, *choices):
-        if not self.parsed:
-            self.parse()
-        if self.events:
-            if not choices:
-                return True
-            for choice in choices:
-                if isinstance(self.events[0], choice):
-                    return True
-        return False
-
-    def peek_event(self):
-        if not self.parsed:
-            self.parse()
-        return self.events[0]
-
-class CanonicalLoader(CanonicalScanner, CanonicalParser,
-        yaml.composer.Composer, yaml.constructor.Constructor, yaml.resolver.Resolver):
-
-    def __init__(self, stream):
-        if hasattr(stream, 'read'):
-            stream = stream.read()
-        CanonicalScanner.__init__(self, stream)
-        CanonicalParser.__init__(self)
-        yaml.composer.Composer.__init__(self)
-        yaml.constructor.Constructor.__init__(self)
-        yaml.resolver.Resolver.__init__(self)
-
-yaml.CanonicalLoader = CanonicalLoader
-
-def canonical_scan(stream):
-    return yaml.scan(stream, Loader=CanonicalLoader)
-
-yaml.canonical_scan = canonical_scan
-
-def canonical_parse(stream):
-    return yaml.parse(stream, Loader=CanonicalLoader)
-
-yaml.canonical_parse = canonical_parse
-
-def canonical_compose(stream):
-    return yaml.compose(stream, Loader=CanonicalLoader)
-
-yaml.canonical_compose = canonical_compose
-
-def canonical_compose_all(stream):
-    return yaml.compose_all(stream, Loader=CanonicalLoader)
-
-yaml.canonical_compose_all = canonical_compose_all
-
-def canonical_load(stream):
-    return yaml.load(stream, Loader=CanonicalLoader)
-
-yaml.canonical_load = canonical_load
-
-def canonical_load_all(stream):
-    return yaml.load_all(stream, Loader=CanonicalLoader)
-
-yaml.canonical_load_all = canonical_load_all
-
diff --git a/tests/lib3/test_all.py b/tests/lib3/test_all.py
deleted file mode 100644
index 72a5067..0000000
--- a/tests/lib3/test_all.py
+++ /dev/null
@@ -1,15 +0,0 @@
-
-import sys, yaml, test_appliance
-
-def main(args=None):
-    collections = []
-    import test_yaml
-    collections.append(test_yaml)
-    if yaml.__with_libyaml__:
-        import test_yaml_ext
-        collections.append(test_yaml_ext)
-    return test_appliance.run(collections, args)
-
-if __name__ == '__main__':
-    main()
-
diff --git a/tests/lib3/test_appliance.py b/tests/lib3/test_appliance.py
deleted file mode 100644
index b6f956d..0000000
--- a/tests/lib3/test_appliance.py
+++ /dev/null
@@ -1,147 +0,0 @@
-
-import sys, os, os.path, types, traceback, pprint
-
-DATA = 'tests/data'
-
-def find_test_functions(collections):
-    if not isinstance(collections, list):
-        collections = [collections]
-    functions = []
-    for collection in collections:
-        if not isinstance(collection, dict):
-            collection = vars(collection)
-        for key in sorted(collection):
-            value = collection[key]
-            if isinstance(value, types.FunctionType) and hasattr(value, 'unittest'):
-                functions.append(value)
-    return functions
-
-def find_test_filenames(directory):
-    filenames = {}
-    for filename in os.listdir(directory):
-        if os.path.isfile(os.path.join(directory, filename)):
-            base, ext = os.path.splitext(filename)
-            if base.endswith('-py2'):
-                continue
-            filenames.setdefault(base, []).append(ext)
-    filenames = sorted(filenames.items())
-    return filenames
-
-def parse_arguments(args):
-    if args is None:
-        args = sys.argv[1:]
-    verbose = False
-    if '-v' in args:
-        verbose = True
-        args.remove('-v')
-    if '--verbose' in args:
-        verbose = True
-        args.remove('--verbose')
-    if 'YAML_TEST_VERBOSE' in os.environ:
-        verbose = True
-    include_functions = []
-    if args:
-        include_functions.append(args.pop(0))
-    if 'YAML_TEST_FUNCTIONS' in os.environ:
-        include_functions.extend(os.environ['YAML_TEST_FUNCTIONS'].split())
-    include_filenames = []
-    include_filenames.extend(args)
-    if 'YAML_TEST_FILENAMES' in os.environ:
-        include_filenames.extend(os.environ['YAML_TEST_FILENAMES'].split())
-    return include_functions, include_filenames, verbose
-
-def execute(function, filenames, verbose):
-    name = function.__name__
-    if verbose:
-        sys.stdout.write('='*75+'\n')
-        sys.stdout.write('%s(%s)...\n' % (name, ', '.join(filenames)))
-    try:
-        function(verbose=verbose, *filenames)
-    except Exception as exc:
-        info = sys.exc_info()
-        if isinstance(exc, AssertionError):
-            kind = 'FAILURE'
-        else:
-            kind = 'ERROR'
-        if verbose:
-            traceback.print_exc(limit=1, file=sys.stdout)
-        else:
-            sys.stdout.write(kind[0])
-            sys.stdout.flush()
-    else:
-        kind = 'SUCCESS'
-        info = None
-        if not verbose:
-            sys.stdout.write('.')
-    sys.stdout.flush()
-    return (name, filenames, kind, info)
-
-def display(results, verbose):
-    if results and not verbose:
-        sys.stdout.write('\n')
-    total = len(results)
-    failures = 0
-    errors = 0
-    for name, filenames, kind, info in results:
-        if kind == 'SUCCESS':
-            continue
-        if kind == 'FAILURE':
-            failures += 1
-        if kind == 'ERROR':
-            errors += 1
-        sys.stdout.write('='*75+'\n')
-        sys.stdout.write('%s(%s): %s\n' % (name, ', '.join(filenames), kind))
-        if kind == 'ERROR':
-            traceback.print_exception(file=sys.stdout, *info)
-        else:
-            sys.stdout.write('Traceback (most recent call last):\n')
-            traceback.print_tb(info[2], file=sys.stdout)
-            sys.stdout.write('%s: see below\n' % info[0].__name__)
-            sys.stdout.write('~'*75+'\n')
-            for arg in info[1].args:
-                pprint.pprint(arg, stream=sys.stdout)
-        for filename in filenames:
-            sys.stdout.write('-'*75+'\n')
-            sys.stdout.write('%s:\n' % filename)
-            data = open(filename, 'r', errors='replace').read()
-            sys.stdout.write(data)
-            if data and data[-1] != '\n':
-                sys.stdout.write('\n')
-    sys.stdout.write('='*75+'\n')
-    sys.stdout.write('TESTS: %s\n' % total)
-    if failures:
-        sys.stdout.write('FAILURES: %s\n' % failures)
-    if errors:
-        sys.stdout.write('ERRORS: %s\n' % errors)
-    return not (failures or errors)
-
-def run(collections, args=None):
-    test_functions = find_test_functions(collections)
-    test_filenames = find_test_filenames(DATA)
-    include_functions, include_filenames, verbose = parse_arguments(args)
-    results = []
-    for function in test_functions:
-        if include_functions and function.__name__ not in include_functions:
-            continue
-        if function.unittest:
-            for base, exts in test_filenames:
-                if include_filenames and base not in include_filenames:
-                    continue
-                filenames = []
-                for ext in function.unittest:
-                    if ext not in exts:
-                        break
-                    filenames.append(os.path.join(DATA, base+ext))
-                else:
-                    skip_exts = getattr(function, 'skip', [])
-                    for skip_ext in skip_exts:
-                        if skip_ext in exts:
-                            break
-                    else:
-                        result = execute(function, filenames, verbose)
-                        results.append(result)
-        else:
-            result = execute(function, [], verbose)
-            results.append(result)
-    return display(results, verbose=verbose)
-
diff --git a/tests/lib3/test_build.py b/tests/lib3/test_build.py
deleted file mode 100644
index 901e8ed..0000000
--- a/tests/lib3/test_build.py
+++ /dev/null
@@ -1,10 +0,0 @@
-
-if __name__ == '__main__':
-    import sys, os, distutils.util
-    build_lib = 'build/lib'
-    build_lib_ext = os.path.join('build', 'lib.%s-%s' % (distutils.util.get_platform(), sys.version[0:3]))
-    sys.path.insert(0, build_lib)
-    sys.path.insert(0, build_lib_ext)
-    import test_yaml, test_appliance
-    test_appliance.run(test_yaml)
-
diff --git a/tests/lib3/test_build_ext.py b/tests/lib3/test_build_ext.py
deleted file mode 100644
index ff195d5..0000000
--- a/tests/lib3/test_build_ext.py
+++ /dev/null
@@ -1,11 +0,0 @@
-
-
-if __name__ == '__main__':
-    import sys, os, distutils.util
-    build_lib = 'build/lib'
-    build_lib_ext = os.path.join('build', 'lib.%s-%s' % (distutils.util.get_platform(), sys.version[0:3]))
-    sys.path.insert(0, build_lib)
-    sys.path.insert(0, build_lib_ext)
-    import test_yaml_ext, test_appliance
-    test_appliance.run(test_yaml_ext)
-
diff --git a/tests/lib3/test_canonical.py b/tests/lib3/test_canonical.py
deleted file mode 100644
index a3b1153..0000000
--- a/tests/lib3/test_canonical.py
+++ /dev/null
@@ -1,40 +0,0 @@
-
-import yaml, canonical
-
-def test_canonical_scanner(canonical_filename, verbose=False):
-    data = open(canonical_filename, 'rb').read()
-    tokens = list(yaml.canonical_scan(data))
-    assert tokens, tokens
-    if verbose:
-        for token in tokens:
-            print(token)
-
-test_canonical_scanner.unittest = ['.canonical']
-
-def test_canonical_parser(canonical_filename, verbose=False):
-    data = open(canonical_filename, 'rb').read()
-    events = list(yaml.canonical_parse(data))
-    assert events, events
-    if verbose:
-        for event in events:
-            print(event)
-
-test_canonical_parser.unittest = ['.canonical']
-
-def test_canonical_error(data_filename, canonical_filename, verbose=False):
-    data = open(data_filename, 'rb').read()
-    try:
-        output = list(yaml.canonical_load_all(data))
-    except yaml.YAMLError as exc:
-        if verbose:
-            print(exc)
-    else:
-        raise AssertionError("expected an exception")
-
-test_canonical_error.unittest = ['.data', '.canonical']
-test_canonical_error.skip = ['.empty']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_constructor.py b/tests/lib3/test_constructor.py
deleted file mode 100644
index 71caa8e..0000000
--- a/tests/lib3/test_constructor.py
+++ /dev/null
@@ -1,259 +0,0 @@
-
-import yaml
-import pprint
-
-import datetime
-import yaml.tokens
-
-def execute(code):
-    global value
-    exec(code)
-    return value
-
-def _make_objects():
-    global MyLoader, MyDumper, MyTestClass1, MyTestClass2, MyTestClass3, YAMLObject1, YAMLObject2,  \
-            AnObject, AnInstance, AState, ACustomState, InitArgs, InitArgsWithState,    \
-            NewArgs, NewArgsWithState, Reduce, ReduceWithState, MyInt, MyList, MyDict,  \
-            FixedOffset, today, execute
-
-    class MyLoader(yaml.DangerLoader):
-        pass
-    class MyDumper(yaml.DangerDumper):
-        pass
-
-    class MyTestClass1:
-        def __init__(self, x, y=0, z=0):
-            self.x = x
-            self.y = y
-            self.z = z
-        def __eq__(self, other):
-            if isinstance(other, MyTestClass1):
-                return self.__class__, self.__dict__ == other.__class__, other.__dict__
-            else:
-                return False
-
-    def construct1(constructor, node):
-        mapping = constructor.construct_mapping(node)
-        return MyTestClass1(**mapping)
-    def represent1(representer, native):
-        return representer.represent_mapping("!tag1", native.__dict__)
-
-    yaml.add_constructor("!tag1", construct1, Loader=MyLoader)
-    yaml.add_representer(MyTestClass1, represent1, Dumper=MyDumper)
-
-    class MyTestClass2(MyTestClass1, yaml.YAMLObject):
-        yaml_loader = MyLoader
-        yaml_dumper = MyDumper
-        yaml_tag = "!tag2"
-        def from_yaml(cls, constructor, node):
-            x = constructor.construct_yaml_int(node)
-            return cls(x=x)
-        from_yaml = classmethod(from_yaml)
-        def to_yaml(cls, representer, native):
-            return representer.represent_scalar(cls.yaml_tag, str(native.x))
-        to_yaml = classmethod(to_yaml)
-
-    class MyTestClass3(MyTestClass2):
-        yaml_tag = "!tag3"
-        def from_yaml(cls, constructor, node):
-            mapping = constructor.construct_mapping(node)
-            if '=' in mapping:
-                x = mapping['=']
-                del mapping['=']
-                mapping['x'] = x
-            return cls(**mapping)
-        from_yaml = classmethod(from_yaml)
-        def to_yaml(cls, representer, native):
-            return representer.represent_mapping(cls.yaml_tag, native.__dict__)
-        to_yaml = classmethod(to_yaml)
-
-    class YAMLObject1(yaml.YAMLObject):
-        yaml_loader = MyLoader
-        yaml_dumper = MyDumper
-        yaml_tag = '!foo'
-        def __init__(self, my_parameter=None, my_another_parameter=None):
-            self.my_parameter = my_parameter
-            self.my_another_parameter = my_another_parameter
-        def __eq__(self, other):
-            if isinstance(other, YAMLObject1):
-                return self.__class__, self.__dict__ == other.__class__, other.__dict__
-            else:
-                return False
-
-    class YAMLObject2(yaml.YAMLObject):
-        yaml_loader = MyLoader
-        yaml_dumper = MyDumper
-        yaml_tag = '!bar'
-        def __init__(self, foo=1, bar=2, baz=3):
-            self.foo = foo
-            self.bar = bar
-            self.baz = baz
-        def __getstate__(self):
-            return {1: self.foo, 2: self.bar, 3: self.baz}
-        def __setstate__(self, state):
-            self.foo = state[1]
-            self.bar = state[2]
-            self.baz = state[3]
-        def __eq__(self, other):
-            if isinstance(other, YAMLObject2):
-                return self.__class__, self.__dict__ == other.__class__, other.__dict__
-            else:
-                return False
-
-    class AnObject:
-        def __new__(cls, foo=None, bar=None, baz=None):
-            self = object.__new__(cls)
-            self.foo = foo
-            self.bar = bar
-            self.baz = baz
-            return self
-        def __cmp__(self, other):
-            return cmp((type(self), self.foo, self.bar, self.baz),
-                    (type(other), other.foo, other.bar, other.baz))
-        def __eq__(self, other):
-            return type(self) is type(other) and    \
-                    (self.foo, self.bar, self.baz) == (other.foo, other.bar, other.baz)
-
-    class AnInstance:
-        def __init__(self, foo=None, bar=None, baz=None):
-            self.foo = foo
-            self.bar = bar
-            self.baz = baz
-        def __cmp__(self, other):
-            return cmp((type(self), self.foo, self.bar, self.baz),
-                    (type(other), other.foo, other.bar, other.baz))
-        def __eq__(self, other):
-            return type(self) is type(other) and    \
-                    (self.foo, self.bar, self.baz) == (other.foo, other.bar, other.baz)
-
-    class AState(AnInstance):
-        def __getstate__(self):
-            return {
-                '_foo': self.foo,
-                '_bar': self.bar,
-                '_baz': self.baz,
-            }
-        def __setstate__(self, state):
-            self.foo = state['_foo']
-            self.bar = state['_bar']
-            self.baz = state['_baz']
-
-    class ACustomState(AnInstance):
-        def __getstate__(self):
-            return (self.foo, self.bar, self.baz)
-        def __setstate__(self, state):
-            self.foo, self.bar, self.baz = state
-
-    class NewArgs(AnObject):
-        def __getnewargs__(self):
-            return (self.foo, self.bar, self.baz)
-        def __getstate__(self):
-            return {}
-
-    class NewArgsWithState(AnObject):
-        def __getnewargs__(self):
-            return (self.foo, self.bar)
-        def __getstate__(self):
-            return self.baz
-        def __setstate__(self, state):
-            self.baz = state
-
-    InitArgs = NewArgs
-
-    InitArgsWithState = NewArgsWithState
-
-    class Reduce(AnObject):
-        def __reduce__(self):
-            return self.__class__, (self.foo, self.bar, self.baz)
-
-    class ReduceWithState(AnObject):
-        def __reduce__(self):
-            return self.__class__, (self.foo, self.bar), self.baz
-        def __setstate__(self, state):
-            self.baz = state
-
-    class MyInt(int):
-        def __eq__(self, other):
-            return type(self) is type(other) and int(self) == int(other)
-
-    class MyList(list):
-        def __init__(self, n=1):
-            self.extend([None]*n)
-        def __eq__(self, other):
-            return type(self) is type(other) and list(self) == list(other)
-
-    class MyDict(dict):
-        def __init__(self, n=1):
-            for k in range(n):
-                self[k] = None
-        def __eq__(self, other):
-            return type(self) is type(other) and dict(self) == dict(other)
-
-    class FixedOffset(datetime.tzinfo):
-        def __init__(self, offset, name):
-            self.__offset = datetime.timedelta(minutes=offset)
-            self.__name = name
-        def utcoffset(self, dt):
-            return self.__offset
-        def tzname(self, dt):
-            return self.__name
-        def dst(self, dt):
-            return datetime.timedelta(0)
-
-    today = datetime.date.today()
-
-def _load_code(expression):
-    return eval(expression)
-
-def _serialize_value(data):
-    if isinstance(data, list):
-        return '[%s]' % ', '.join(map(_serialize_value, data))
-    elif isinstance(data, dict):
-        items = []
-        for key, value in data.items():
-            key = _serialize_value(key)
-            value = _serialize_value(value)
-            items.append("%s: %s" % (key, value))
-        items.sort()
-        return '{%s}' % ', '.join(items)
-    elif isinstance(data, datetime.datetime):
-        return repr(data.utctimetuple())
-    elif isinstance(data, float) and data != data:
-        return '?'
-    else:
-        return str(data)
-
-def test_constructor_types(data_filename, code_filename, verbose=False):
-    _make_objects()
-    native1 = None
-    native2 = None
-    try:
-        native1 = list(yaml.load_all(open(data_filename, 'rb'), Loader=MyLoader))
-        if len(native1) == 1:
-            native1 = native1[0]
-        native2 = _load_code(open(code_filename, 'rb').read())
-        try:
-            if native1 == native2:
-                return
-        except TypeError:
-            pass
-        if verbose:
-            print("SERIALIZED NATIVE1:")
-            print(_serialize_value(native1))
-            print("SERIALIZED NATIVE2:")
-            print(_serialize_value(native2))
-        assert _serialize_value(native1) == _serialize_value(native2), (native1, native2)
-    finally:
-        if verbose:
-            print("NATIVE1:")
-            pprint.pprint(native1)
-            print("NATIVE2:")
-            pprint.pprint(native2)
-
-test_constructor_types.unittest = ['.data', '.code']
-
-if __name__ == '__main__':
-    import sys, test_constructor
-    sys.modules['test_constructor'] = sys.modules['__main__']
-    import test_appliance
-    test_appliance.run(globals())
diff --git a/tests/lib3/test_emitter.py b/tests/lib3/test_emitter.py
deleted file mode 100644
index 90d1652..0000000
--- a/tests/lib3/test_emitter.py
+++ /dev/null
@@ -1,100 +0,0 @@
-
-import yaml
-
-def _compare_events(events1, events2):
-    assert len(events1) == len(events2), (events1, events2)
-    for event1, event2 in zip(events1, events2):
-        assert event1.__class__ == event2.__class__, (event1, event2)
-        if isinstance(event1, yaml.NodeEvent):
-            assert event1.anchor == event2.anchor, (event1, event2)
-        if isinstance(event1, yaml.CollectionStartEvent):
-            assert event1.tag == event2.tag, (event1, event2)
-        if isinstance(event1, yaml.ScalarEvent):
-            if True not in event1.implicit+event2.implicit:
-                assert event1.tag == event2.tag, (event1, event2)
-            assert event1.value == event2.value, (event1, event2)
-
-def test_emitter_on_data(data_filename, canonical_filename, verbose=False):
-    events = list(yaml.parse(open(data_filename, 'rb')))
-    output = yaml.emit(events)
-    if verbose:
-        print("OUTPUT:")
-        print(output)
-    new_events = list(yaml.parse(output))
-    _compare_events(events, new_events)
-
-test_emitter_on_data.unittest = ['.data', '.canonical']
-
-def test_emitter_on_canonical(canonical_filename, verbose=False):
-    events = list(yaml.parse(open(canonical_filename, 'rb')))
-    for canonical in [False, True]:
-        output = yaml.emit(events, canonical=canonical)
-        if verbose:
-            print("OUTPUT (canonical=%s):" % canonical)
-            print(output)
-        new_events = list(yaml.parse(output))
-        _compare_events(events, new_events)
-
-test_emitter_on_canonical.unittest = ['.canonical']
-
-def test_emitter_styles(data_filename, canonical_filename, verbose=False):
-    for filename in [data_filename, canonical_filename]:
-        events = list(yaml.parse(open(filename, 'rb')))
-        for flow_style in [False, True]:
-            for style in ['|', '>', '"', '\'', '']:
-                styled_events = []
-                for event in events:
-                    if isinstance(event, yaml.ScalarEvent):
-                        event = yaml.ScalarEvent(event.anchor, event.tag,
-                                event.implicit, event.value, style=style)
-                    elif isinstance(event, yaml.SequenceStartEvent):
-                        event = yaml.SequenceStartEvent(event.anchor, event.tag,
-                                event.implicit, flow_style=flow_style)
-                    elif isinstance(event, yaml.MappingStartEvent):
-                        event = yaml.MappingStartEvent(event.anchor, event.tag,
-                                event.implicit, flow_style=flow_style)
-                    styled_events.append(event)
-                output = yaml.emit(styled_events)
-                if verbose:
-                    print("OUTPUT (filename=%r, flow_style=%r, style=%r)" % (filename, flow_style, style))
-                    print(output)
-                new_events = list(yaml.parse(output))
-                _compare_events(events, new_events)
-
-test_emitter_styles.unittest = ['.data', '.canonical']
-
-class EventsLoader(yaml.Loader):
-
-    def construct_event(self, node):
-        if isinstance(node, yaml.ScalarNode):
-            mapping = {}
-        else:
-            mapping = self.construct_mapping(node)
-        class_name = str(node.tag[1:])+'Event'
-        if class_name in ['AliasEvent', 'ScalarEvent', 'SequenceStartEvent', 'MappingStartEvent']:
-            mapping.setdefault('anchor', None)
-        if class_name in ['ScalarEvent', 'SequenceStartEvent', 'MappingStartEvent']:
-            mapping.setdefault('tag', None)
-        if class_name in ['SequenceStartEvent', 'MappingStartEvent']:
-            mapping.setdefault('implicit', True)
-        if class_name == 'ScalarEvent':
-            mapping.setdefault('implicit', (False, True))
-            mapping.setdefault('value', '')
-        value = getattr(yaml, class_name)(**mapping)
-        return value
-
-EventsLoader.add_constructor(None, EventsLoader.construct_event)
-
-def test_emitter_events(events_filename, verbose=False):
-    events = list(yaml.load(open(events_filename, 'rb'), Loader=EventsLoader))
-    output = yaml.emit(events)
-    if verbose:
-        print("OUTPUT:")
-        print(output)
-    new_events = list(yaml.parse(output))
-    _compare_events(events, new_events)
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_errors.py b/tests/lib3/test_errors.py
deleted file mode 100644
index a3f86af..0000000
--- a/tests/lib3/test_errors.py
+++ /dev/null
@@ -1,67 +0,0 @@
-
-import yaml, test_emitter
-
-def test_loader_error(error_filename, verbose=False):
-    try:
-        list(yaml.load_all(open(error_filename, 'rb')))
-    except yaml.YAMLError as exc:
-        if verbose:
-            print("%s:" % exc.__class__.__name__, exc)
-    else:
-        raise AssertionError("expected an exception")
-
-test_loader_error.unittest = ['.loader-error']
-
-def test_loader_error_string(error_filename, verbose=False):
-    try:
-        list(yaml.load_all(open(error_filename, 'rb').read()))
-    except yaml.YAMLError as exc:
-        if verbose:
-            print("%s:" % exc.__class__.__name__, exc)
-    else:
-        raise AssertionError("expected an exception")
-
-test_loader_error_string.unittest = ['.loader-error']
-
-def test_loader_error_single(error_filename, verbose=False):
-    try:
-        yaml.load(open(error_filename, 'rb').read())
-    except yaml.YAMLError as exc:
-        if verbose:
-            print("%s:" % exc.__class__.__name__, exc)
-    else:
-        raise AssertionError("expected an exception")
-
-test_loader_error_single.unittest = ['.single-loader-error']
-
-def test_emitter_error(error_filename, verbose=False):
-    events = list(yaml.load(open(error_filename, 'rb'),
-                    Loader=test_emitter.EventsLoader))
-    try:
-        yaml.emit(events)
-    except yaml.YAMLError as exc:
-        if verbose:
-            print("%s:" % exc.__class__.__name__, exc)
-    else:
-        raise AssertionError("expected an exception")
-
-test_emitter_error.unittest = ['.emitter-error']
-
-def test_dumper_error(error_filename, verbose=False):
-    code = open(error_filename, 'rb').read()
-    try:
-        import yaml
-        from io import StringIO
-        exec(code)
-    except yaml.YAMLError as exc:
-        if verbose:
-            print("%s:" % exc.__class__.__name__, exc)
-    else:
-        raise AssertionError("expected an exception")
-
-test_dumper_error.unittest = ['.dumper-error']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_input_output.py b/tests/lib3/test_input_output.py
deleted file mode 100644
index 50f0122..0000000
--- a/tests/lib3/test_input_output.py
+++ /dev/null
@@ -1,136 +0,0 @@
-
-import yaml
-import codecs, io, tempfile, os, os.path
-
-def test_unicode_input(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
-    value = ' '.join(data.split())
-    output = yaml.load(data)
-    assert output == value, (output, value)
-    output = yaml.load(io.StringIO(data))
-    assert output == value, (output, value)
-    for input in [data.encode('utf-8'),
-                    codecs.BOM_UTF8+data.encode('utf-8'),
-                    codecs.BOM_UTF16_BE+data.encode('utf-16-be'),
-                    codecs.BOM_UTF16_LE+data.encode('utf-16-le')]:
-        if verbose:
-            print("INPUT:", repr(input[:10]), "...")
-        output = yaml.load(input)
-        assert output == value, (output, value)
-        output = yaml.load(io.BytesIO(input))
-        assert output == value, (output, value)
-
-test_unicode_input.unittest = ['.unicode']
-
-def test_unicode_input_errors(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
-    for input in [data.encode('utf-16-be'),
-            data.encode('utf-16-le'),
-            codecs.BOM_UTF8+data.encode('utf-16-be'),
-            codecs.BOM_UTF8+data.encode('utf-16-le')]:
-
-        try:
-            yaml.load(input)
-        except yaml.YAMLError as exc:
-            if verbose:
-                print(exc)
-        else:
-            raise AssertionError("expected an exception")
-        try:
-            yaml.load(io.BytesIO(input))
-        except yaml.YAMLError as exc:
-            if verbose:
-                print(exc)
-        else:
-            raise AssertionError("expected an exception")
-
-test_unicode_input_errors.unittest = ['.unicode']
-
-def test_unicode_output(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
-    value = ' '.join(data.split())
-    for allow_unicode in [False, True]:
-        data1 = yaml.dump(value, allow_unicode=allow_unicode)
-        for encoding in [None, 'utf-8', 'utf-16-be', 'utf-16-le']:
-            stream = io.StringIO()
-            yaml.dump(value, stream, encoding=encoding, allow_unicode=allow_unicode)
-            data2 = stream.getvalue()
-            data3 = yaml.dump(value, encoding=encoding, allow_unicode=allow_unicode)
-            if encoding is not None:
-                assert isinstance(data3, bytes)
-                data3 = data3.decode(encoding)
-            stream = io.BytesIO()
-            if encoding is None:
-                try:
-                    yaml.dump(value, stream, encoding=encoding, allow_unicode=allow_unicode)
-                except TypeError as exc:
-                    if verbose:
-                        print(exc)
-                    data4 = None
-                else:
-                    raise AssertionError("expected an exception")
-            else:
-                yaml.dump(value, stream, encoding=encoding, allow_unicode=allow_unicode)
-                data4 = stream.getvalue()
-                if verbose:
-                    print("BYTES:", data4[:50])
-                data4 = data4.decode(encoding)
-
-            assert isinstance(data1, str), (type(data1), encoding)
-            assert isinstance(data2, str), (type(data2), encoding)
-
-test_unicode_output.unittest = ['.unicode']
-
-def test_file_output(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
-    handle, filename = tempfile.mkstemp()
-    os.close(handle)
-    try:
-        stream = io.StringIO()
-        yaml.dump(data, stream, allow_unicode=True)
-        data1 = stream.getvalue()
-        stream = io.BytesIO()
-        yaml.dump(data, stream, encoding='utf-16-le', allow_unicode=True)
-        data2 = stream.getvalue().decode('utf-16-le')[1:]
-        stream = open(filename, 'w', encoding='utf-16-le')
-        yaml.dump(data, stream, allow_unicode=True)
-        stream.close()
-        data3 = open(filename, 'r', encoding='utf-16-le').read()
-        stream = open(filename, 'wb')
-        yaml.dump(data, stream, encoding='utf-8', allow_unicode=True)
-        stream.close()
-        data4 = open(filename, 'r', encoding='utf-8').read()
-        assert data1 == data2, (data1, data2)
-        assert data1 == data3, (data1, data3)
-        assert data1 == data4, (data1, data4)
-    finally:
-        if os.path.exists(filename):
-            os.unlink(filename)
-
-test_file_output.unittest = ['.unicode']
-
-def test_unicode_transfer(unicode_filename, verbose=False):
-    data = open(unicode_filename, 'rb').read().decode('utf-8')
-    for encoding in [None, 'utf-8', 'utf-16-be', 'utf-16-le']:
-        input = data
-        if encoding is not None:
-            input = ('\ufeff'+input).encode(encoding)
-        output1 = yaml.emit(yaml.parse(input), allow_unicode=True)
-        if encoding is None:
-            stream = io.StringIO()
-        else:
-            stream = io.BytesIO()
-        yaml.emit(yaml.parse(input), stream, allow_unicode=True)
-        output2 = stream.getvalue()
-        assert isinstance(output1, str), (type(output1), encoding)
-        if encoding is None:
-            assert isinstance(output2, str), (type(output1), encoding)
-        else:
-            assert isinstance(output2, bytes), (type(output1), encoding)
-            output2.decode(encoding)
-
-test_unicode_transfer.unittest = ['.unicode']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
diff --git a/tests/lib3/test_mark.py b/tests/lib3/test_mark.py
deleted file mode 100644
index 09eea2e..0000000
--- a/tests/lib3/test_mark.py
+++ /dev/null
@@ -1,32 +0,0 @@
-
-import yaml
-
-def test_marks(marks_filename, verbose=False):
-    inputs = open(marks_filename, 'r').read().split('---\n')[1:]
-    for input in inputs:
-        index = 0
-        line = 0
-        column = 0
-        while input[index] != '*':
-            if input[index] == '\n':
-                line += 1
-                column = 0
-            else:
-                column += 1
-            index += 1
-        mark = yaml.Mark(marks_filename, index, line, column, input, index)
-        snippet = mark.get_snippet(indent=2, max_length=79)
-        if verbose:
-            print(snippet)
-        assert isinstance(snippet, str), type(snippet)
-        assert snippet.count('\n') == 1, snippet.count('\n')
-        data, pointer = snippet.split('\n')
-        assert len(data) < 82, len(data)
-        assert data[len(pointer)-1] == '*', data[len(pointer)-1]
-
-test_marks.unittest = ['.marks']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_reader.py b/tests/lib3/test_reader.py
deleted file mode 100644
index c07b346..0000000
--- a/tests/lib3/test_reader.py
+++ /dev/null
@@ -1,34 +0,0 @@
-
-import yaml.reader
-
-def _run_reader(data, verbose):
-    try:
-        stream = yaml.reader.Reader(data)
-        while stream.peek() != '\0':
-            stream.forward()
-    except yaml.reader.ReaderError as exc:
-        if verbose:
-            print(exc)
-    else:
-        raise AssertionError("expected an exception")
-
-def test_stream_error(error_filename, verbose=False):
-    _run_reader(open(error_filename, 'rb'), verbose)
-    _run_reader(open(error_filename, 'rb').read(), verbose)
-    for encoding in ['utf-8', 'utf-16-le', 'utf-16-be']:
-        try:
-            data = open(error_filename, 'rb').read().decode(encoding)
-            break
-        except UnicodeDecodeError:
-            pass
-    else:
-        return
-    _run_reader(data, verbose)
-    _run_reader(open(error_filename, encoding=encoding), verbose)
-
-test_stream_error.unittest = ['.stream-error']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_recursive.py b/tests/lib3/test_recursive.py
deleted file mode 100644
index 31f2344..0000000
--- a/tests/lib3/test_recursive.py
+++ /dev/null
@@ -1,50 +0,0 @@
-
-import yaml
-
-class AnInstance:
-
-    def __init__(self, foo, bar):
-        self.foo = foo
-        self.bar = bar
-
-    def __repr__(self):
-        try:
-            return "%s(foo=%r, bar=%r)" % (self.__class__.__name__,
-                    self.foo, self.bar)
-        except RuntimeError:
-            return "%s(foo=..., bar=...)" % self.__class__.__name__
-
-class AnInstanceWithState(AnInstance):
-
-    def __getstate__(self):
-        return {'attributes': [self.foo, self.bar]}
-
-    def __setstate__(self, state):
-        self.foo, self.bar = state['attributes']
-
-def test_recursive(recursive_filename, verbose=False):
-    context = globals().copy()
-    exec(open(recursive_filename, 'rb').read(), context)
-    value1 = context['value']
-    output1 = None
-    value2 = None
-    output2 = None
-    try:
-        output1 = yaml.danger_dump(value1)
-        value2 = yaml.danger_load(output1)
-        output2 = yaml.danger_dump(value2)
-        assert output1 == output2, (output1, output2)
-    finally:
-        if verbose:
-            print("VALUE1:", value1)
-            print("VALUE2:", value2)
-            print("OUTPUT1:")
-            print(output1)
-            print("OUTPUT2:")
-            print(output2)
-
-test_recursive.unittest = ['.recursive']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
diff --git a/tests/lib3/test_representer.py b/tests/lib3/test_representer.py
deleted file mode 100644
index 10d4a8f..0000000
--- a/tests/lib3/test_representer.py
+++ /dev/null
@@ -1,43 +0,0 @@
-
-import yaml
-import test_constructor
-import pprint
-
-def test_representer_types(code_filename, verbose=False):
-    test_constructor._make_objects()
-    for allow_unicode in [False, True]:
-        for encoding in ['utf-8', 'utf-16-be', 'utf-16-le']:
-            native1 = test_constructor._load_code(open(code_filename, 'rb').read())
-            native2 = None
-            try:
-                output = yaml.dump(native1, Dumper=test_constructor.MyDumper,
-                            allow_unicode=allow_unicode, encoding=encoding)
-                native2 = yaml.load(output, Loader=test_constructor.MyLoader)
-                try:
-                    if native1 == native2:
-                        continue
-                except TypeError:
-                    pass
-                value1 = test_constructor._serialize_value(native1)
-                value2 = test_constructor._serialize_value(native2)
-                if verbose:
-                    print("SERIALIZED NATIVE1:")
-                    print(value1)
-                    print("SERIALIZED NATIVE2:")
-                    print(value2)
-                assert value1 == value2, (native1, native2)
-            finally:
-                if verbose:
-                    print("NATIVE1:")
-                    pprint.pprint(native1)
-                    print("NATIVE2:")
-                    pprint.pprint(native2)
-                    print("OUTPUT:")
-                    print(output)
-
-test_representer_types.unittest = ['.code']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_resolver.py b/tests/lib3/test_resolver.py
deleted file mode 100644
index f059dab..0000000
--- a/tests/lib3/test_resolver.py
+++ /dev/null
@@ -1,92 +0,0 @@
-
-import yaml
-import pprint
-
-def test_implicit_resolver(data_filename, detect_filename, verbose=False):
-    correct_tag = None
-    node = None
-    try:
-        correct_tag = open(detect_filename, 'r').read().strip()
-        node = yaml.compose(open(data_filename, 'rb'))
-        assert isinstance(node, yaml.SequenceNode), node
-        for scalar in node.value:
-            assert isinstance(scalar, yaml.ScalarNode), scalar
-            assert scalar.tag == correct_tag, (scalar.tag, correct_tag)
-    finally:
-        if verbose:
-            print("CORRECT TAG:", correct_tag)
-            if hasattr(node, 'value'):
-                print("CHILDREN:")
-                pprint.pprint(node.value)
-
-test_implicit_resolver.unittest = ['.data', '.detect']
-
-def _make_path_loader_and_dumper():
-    global MyLoader, MyDumper
-
-    class MyLoader(yaml.Loader):
-        pass
-    class MyDumper(yaml.Dumper):
-        pass
-
-    yaml.add_path_resolver('!root', [],
-            Loader=MyLoader, Dumper=MyDumper)
-    yaml.add_path_resolver('!root/scalar', [], str,
-            Loader=MyLoader, Dumper=MyDumper)
-    yaml.add_path_resolver('!root/key11/key12/*', ['key11', 'key12'],
-            Loader=MyLoader, Dumper=MyDumper)
-    yaml.add_path_resolver('!root/key21/1/*', ['key21', 1],
-            Loader=MyLoader, Dumper=MyDumper)
-    yaml.add_path_resolver('!root/key31/*/*/key14/map', ['key31', None, None, 'key14'], dict,
-            Loader=MyLoader, Dumper=MyDumper)
-
-    return MyLoader, MyDumper
-
-def _convert_node(node):
-    if isinstance(node, yaml.ScalarNode):
-        return (node.tag, node.value)
-    elif isinstance(node, yaml.SequenceNode):
-        value = []
-        for item in node.value:
-            value.append(_convert_node(item))
-        return (node.tag, value)
-    elif isinstance(node, yaml.MappingNode):
-        value = []
-        for key, item in node.value:
-            value.append((_convert_node(key), _convert_node(item)))
-        return (node.tag, value)
-
-def test_path_resolver_loader(data_filename, path_filename, verbose=False):
-    _make_path_loader_and_dumper()
-    nodes1 = list(yaml.compose_all(open(data_filename, 'rb').read(), Loader=MyLoader))
-    nodes2 = list(yaml.compose_all(open(path_filename, 'rb').read()))
-    try:
-        for node1, node2 in zip(nodes1, nodes2):
-            data1 = _convert_node(node1)
-            data2 = _convert_node(node2)
-            assert data1 == data2, (data1, data2)
-    finally:
-        if verbose:
-            print(yaml.serialize_all(nodes1))
-
-test_path_resolver_loader.unittest = ['.data', '.path']
-
-def test_path_resolver_dumper(data_filename, path_filename, verbose=False):
-    _make_path_loader_and_dumper()
-    for filename in [data_filename, path_filename]:
-        output = yaml.serialize_all(yaml.compose_all(open(filename, 'rb')), Dumper=MyDumper)
-        if verbose:
-            print(output)
-        nodes1 = yaml.compose_all(output)
-        nodes2 = yaml.compose_all(open(data_filename, 'rb'))
-        for node1, node2 in zip(nodes1, nodes2):
-            data1 = _convert_node(node1)
-            data2 = _convert_node(node2)
-            assert data1 == data2, (data1, data2)
-
-test_path_resolver_dumper.unittest = ['.data', '.path']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_structure.py b/tests/lib3/test_structure.py
deleted file mode 100644
index 6d6f59d..0000000
--- a/tests/lib3/test_structure.py
+++ /dev/null
@@ -1,187 +0,0 @@
-
-import yaml, canonical
-import pprint
-
-def _convert_structure(loader):
-    if loader.check_event(yaml.ScalarEvent):
-        event = loader.get_event()
-        if event.tag or event.anchor or event.value:
-            return True
-        else:
-            return None
-    elif loader.check_event(yaml.SequenceStartEvent):
-        loader.get_event()
-        sequence = []
-        while not loader.check_event(yaml.SequenceEndEvent):
-            sequence.append(_convert_structure(loader))
-        loader.get_event()
-        return sequence
-    elif loader.check_event(yaml.MappingStartEvent):
-        loader.get_event()
-        mapping = []
-        while not loader.check_event(yaml.MappingEndEvent):
-            key = _convert_structure(loader)
-            value = _convert_structure(loader)
-            mapping.append((key, value))
-        loader.get_event()
-        return mapping
-    elif loader.check_event(yaml.AliasEvent):
-        loader.get_event()
-        return '*'
-    else:
-        loader.get_event()
-        return '?'
-
-def test_structure(data_filename, structure_filename, verbose=False):
-    nodes1 = []
-    nodes2 = eval(open(structure_filename, 'r').read())
-    try:
-        loader = yaml.Loader(open(data_filename, 'rb'))
-        while loader.check_event():
-            if loader.check_event(yaml.StreamStartEvent, yaml.StreamEndEvent,
-                                yaml.DocumentStartEvent, yaml.DocumentEndEvent):
-                loader.get_event()
-                continue
-            nodes1.append(_convert_structure(loader))
-        if len(nodes1) == 1:
-            nodes1 = nodes1[0]
-        assert nodes1 == nodes2, (nodes1, nodes2)
-    finally:
-        if verbose:
-            print("NODES1:")
-            pprint.pprint(nodes1)
-            print("NODES2:")
-            pprint.pprint(nodes2)
-
-test_structure.unittest = ['.data', '.structure']
-
-def _compare_events(events1, events2, full=False):
-    assert len(events1) == len(events2), (len(events1), len(events2))
-    for event1, event2 in zip(events1, events2):
-        assert event1.__class__ == event2.__class__, (event1, event2)
-        if isinstance(event1, yaml.AliasEvent) and full:
-            assert event1.anchor == event2.anchor, (event1, event2)
-        if isinstance(event1, (yaml.ScalarEvent, yaml.CollectionStartEvent)):
-            if (event1.tag not in [None, '!'] and event2.tag not in [None, '!']) or full:
-                assert event1.tag == event2.tag, (event1, event2)
-        if isinstance(event1, yaml.ScalarEvent):
-            assert event1.value == event2.value, (event1, event2)
-
-def test_parser(data_filename, canonical_filename, verbose=False):
-    events1 = None
-    events2 = None
-    try:
-        events1 = list(yaml.parse(open(data_filename, 'rb')))
-        events2 = list(yaml.canonical_parse(open(canonical_filename, 'rb')))
-        _compare_events(events1, events2)
-    finally:
-        if verbose:
-            print("EVENTS1:")
-            pprint.pprint(events1)
-            print("EVENTS2:")
-            pprint.pprint(events2)
-
-test_parser.unittest = ['.data', '.canonical']
-
-def test_parser_on_canonical(canonical_filename, verbose=False):
-    events1 = None
-    events2 = None
-    try:
-        events1 = list(yaml.parse(open(canonical_filename, 'rb')))
-        events2 = list(yaml.canonical_parse(open(canonical_filename, 'rb')))
-        _compare_events(events1, events2, full=True)
-    finally:
-        if verbose:
-            print("EVENTS1:")
-            pprint.pprint(events1)
-            print("EVENTS2:")
-            pprint.pprint(events2)
-
-test_parser_on_canonical.unittest = ['.canonical']
-
-def _compare_nodes(node1, node2):
-    assert node1.__class__ == node2.__class__, (node1, node2)
-    assert node1.tag == node2.tag, (node1, node2)
-    if isinstance(node1, yaml.ScalarNode):
-        assert node1.value == node2.value, (node1, node2)
-    else:
-        assert len(node1.value) == len(node2.value), (node1, node2)
-        for item1, item2 in zip(node1.value, node2.value):
-            if not isinstance(item1, tuple):
-                item1 = (item1,)
-                item2 = (item2,)
-            for subnode1, subnode2 in zip(item1, item2):
-                _compare_nodes(subnode1, subnode2)
-
-def test_composer(data_filename, canonical_filename, verbose=False):
-    nodes1 = None
-    nodes2 = None
-    try:
-        nodes1 = list(yaml.compose_all(open(data_filename, 'rb')))
-        nodes2 = list(yaml.canonical_compose_all(open(canonical_filename, 'rb')))
-        assert len(nodes1) == len(nodes2), (len(nodes1), len(nodes2))
-        for node1, node2 in zip(nodes1, nodes2):
-            _compare_nodes(node1, node2)
-    finally:
-        if verbose:
-            print("NODES1:")
-            pprint.pprint(nodes1)
-            print("NODES2:")
-            pprint.pprint(nodes2)
-
-test_composer.unittest = ['.data', '.canonical']
-
-def _make_loader():
-    global MyLoader
-
-    class MyLoader(yaml.Loader):
-        def construct_sequence(self, node):
-            return tuple(yaml.Loader.construct_sequence(self, node))
-        def construct_mapping(self, node):
-            pairs = self.construct_pairs(node)
-            pairs.sort(key=(lambda i: str(i)))
-            return pairs
-        def construct_undefined(self, node):
-            return self.construct_scalar(node)
-
-    MyLoader.add_constructor('tag:yaml.org,2002:map', MyLoader.construct_mapping)
-    MyLoader.add_constructor(None, MyLoader.construct_undefined)
-
-def _make_canonical_loader():
-    global MyCanonicalLoader
-
-    class MyCanonicalLoader(yaml.CanonicalLoader):
-        def construct_sequence(self, node):
-            return tuple(yaml.CanonicalLoader.construct_sequence(self, node))
-        def construct_mapping(self, node):
-            pairs = self.construct_pairs(node)
-            pairs.sort(key=(lambda i: str(i)))
-            return pairs
-        def construct_undefined(self, node):
-            return self.construct_scalar(node)
-
-    MyCanonicalLoader.add_constructor('tag:yaml.org,2002:map', MyCanonicalLoader.construct_mapping)
-    MyCanonicalLoader.add_constructor(None, MyCanonicalLoader.construct_undefined)
-
-def test_constructor(data_filename, canonical_filename, verbose=False):
-    _make_loader()
-    _make_canonical_loader()
-    native1 = None
-    native2 = None
-    try:
-        native1 = list(yaml.load_all(open(data_filename, 'rb'), Loader=MyLoader))
-        native2 = list(yaml.load_all(open(canonical_filename, 'rb'), Loader=MyCanonicalLoader))
-        assert native1 == native2, (native1, native2)
-    finally:
-        if verbose:
-            print("NATIVE1:")
-            pprint.pprint(native1)
-            print("NATIVE2:")
-            pprint.pprint(native2)
-
-test_constructor.unittest = ['.data', '.canonical']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_tokens.py b/tests/lib3/test_tokens.py
deleted file mode 100644
index 828945a..0000000
--- a/tests/lib3/test_tokens.py
+++ /dev/null
@@ -1,77 +0,0 @@
-
-import yaml
-import pprint
-
-# Tokens mnemonic:
-# directive:            %
-# document_start:       ---
-# document_end:         ...
-# alias:                *
-# anchor:               &
-# tag:                  !
-# scalar                _
-# block_sequence_start: [[
-# block_mapping_start:  {{
-# block_end:            ]}
-# flow_sequence_start:  [
-# flow_sequence_end:    ]
-# flow_mapping_start:   {
-# flow_mapping_end:     }
-# entry:                ,
-# key:                  ?
-# value:                :
-
-_replaces = {
-    yaml.DirectiveToken: '%',
-    yaml.DocumentStartToken: '---',
-    yaml.DocumentEndToken: '...',
-    yaml.AliasToken: '*',
-    yaml.AnchorToken: '&',
-    yaml.TagToken: '!',
-    yaml.ScalarToken: '_',
-    yaml.BlockSequenceStartToken: '[[',
-    yaml.BlockMappingStartToken: '{{',
-    yaml.BlockEndToken: ']}',
-    yaml.FlowSequenceStartToken: '[',
-    yaml.FlowSequenceEndToken: ']',
-    yaml.FlowMappingStartToken: '{',
-    yaml.FlowMappingEndToken: '}',
-    yaml.BlockEntryToken: ',',
-    yaml.FlowEntryToken: ',',
-    yaml.KeyToken: '?',
-    yaml.ValueToken: ':',
-}
-
-def test_tokens(data_filename, tokens_filename, verbose=False):
-    tokens1 = []
-    tokens2 = open(tokens_filename, 'r').read().split()
-    try:
-        for token in yaml.scan(open(data_filename, 'rb')):
-            if not isinstance(token, (yaml.StreamStartToken, yaml.StreamEndToken)):
-                tokens1.append(_replaces[token.__class__])
-    finally:
-        if verbose:
-            print("TOKENS1:", ' '.join(tokens1))
-            print("TOKENS2:", ' '.join(tokens2))
-    assert len(tokens1) == len(tokens2), (tokens1, tokens2)
-    for token1, token2 in zip(tokens1, tokens2):
-        assert token1 == token2, (token1, token2)
-
-test_tokens.unittest = ['.data', '.tokens']
-
-def test_scanner(data_filename, canonical_filename, verbose=False):
-    for filename in [data_filename, canonical_filename]:
-        tokens = []
-        try:
-            for token in yaml.scan(open(filename, 'rb')):
-                tokens.append(token.__class__.__name__)
-        finally:
-            if verbose:
-                pprint.pprint(tokens)
-
-test_scanner.unittest = ['.data', '.canonical']
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_yaml.py b/tests/lib3/test_yaml.py
deleted file mode 100644
index 0927368..0000000
--- a/tests/lib3/test_yaml.py
+++ /dev/null
@@ -1,18 +0,0 @@
-
-from test_mark import *
-from test_reader import *
-from test_canonical import *
-from test_tokens import *
-from test_structure import *
-from test_errors import *
-from test_resolver import *
-from test_constructor import *
-from test_emitter import *
-from test_representer import *
-from test_recursive import *
-from test_input_output import *
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tests/lib3/test_yaml_ext.py b/tests/lib3/test_yaml_ext.py
deleted file mode 100644
index 93d397b..0000000
--- a/tests/lib3/test_yaml_ext.py
+++ /dev/null
@@ -1,271 +0,0 @@
-
-import _yaml, yaml
-import types, pprint
-
-yaml.PyBaseLoader = yaml.BaseLoader
-yaml.PySafeLoader = yaml.SafeLoader
-yaml.PyLoader = yaml.Loader
-yaml.PyBaseDumper = yaml.BaseDumper
-yaml.PySafeDumper = yaml.SafeDumper
-yaml.PyDumper = yaml.Dumper
-
-old_scan = yaml.scan
-def new_scan(stream, Loader=yaml.CLoader):
-    return old_scan(stream, Loader)
-
-old_parse = yaml.parse
-def new_parse(stream, Loader=yaml.CLoader):
-    return old_parse(stream, Loader)
-
-old_compose = yaml.compose
-def new_compose(stream, Loader=yaml.CLoader):
-    return old_compose(stream, Loader)
-
-old_compose_all = yaml.compose_all
-def new_compose_all(stream, Loader=yaml.CLoader):
-    return old_compose_all(stream, Loader)
-
-old_load = yaml.load
-def new_load(stream, Loader=yaml.CLoader):
-    return old_load(stream, Loader)
-
-old_load_all = yaml.load_all
-def new_load_all(stream, Loader=yaml.CLoader):
-    return old_load_all(stream, Loader)
-
-old_safe_load = yaml.safe_load
-def new_safe_load(stream):
-    return old_load(stream, yaml.CSafeLoader)
-
-old_safe_load_all = yaml.safe_load_all
-def new_safe_load_all(stream):
-    return old_load_all(stream, yaml.CSafeLoader)
-
-old_emit = yaml.emit
-def new_emit(events, stream=None, Dumper=yaml.CDumper, **kwds):
-    return old_emit(events, stream, Dumper, **kwds)
-
-old_serialize = yaml.serialize
-def new_serialize(node, stream, Dumper=yaml.CDumper, **kwds):
-    return old_serialize(node, stream, Dumper, **kwds)
-
-old_serialize_all = yaml.serialize_all
-def new_serialize_all(nodes, stream=None, Dumper=yaml.CDumper, **kwds):
-    return old_serialize_all(nodes, stream, Dumper, **kwds)
-
-old_dump = yaml.dump
-def new_dump(data, stream=None, Dumper=yaml.CDumper, **kwds):
-    return old_dump(data, stream, Dumper, **kwds)
-
-old_dump_all = yaml.dump_all
-def new_dump_all(documents, stream=None, Dumper=yaml.CDumper, **kwds):
-    return old_dump_all(documents, stream, Dumper, **kwds)
-
-old_safe_dump = yaml.safe_dump
-def new_safe_dump(data, stream=None, **kwds):
-    return old_dump(data, stream, yaml.CSafeDumper, **kwds)
-
-old_safe_dump_all = yaml.safe_dump_all
-def new_safe_dump_all(documents, stream=None, **kwds):
-    return old_dump_all(documents, stream, yaml.CSafeDumper, **kwds)
-
-def _set_up():
-    yaml.BaseLoader = yaml.CBaseLoader
-    yaml.SafeLoader = yaml.CSafeLoader
-    yaml.Loader = yaml.CLoader
-    yaml.BaseDumper = yaml.CBaseDumper
-    yaml.SafeDumper = yaml.CSafeDumper
-    yaml.Dumper = yaml.CDumper
-    yaml.scan = new_scan
-    yaml.parse = new_parse
-    yaml.compose = new_compose
-    yaml.compose_all = new_compose_all
-    yaml.load = new_load
-    yaml.load_all = new_load_all
-    yaml.safe_load = new_safe_load
-    yaml.safe_load_all = new_safe_load_all
-    yaml.emit = new_emit
-    yaml.serialize = new_serialize
-    yaml.serialize_all = new_serialize_all
-    yaml.dump = new_dump
-    yaml.dump_all = new_dump_all
-    yaml.safe_dump = new_safe_dump
-    yaml.safe_dump_all = new_safe_dump_all
-
-def _tear_down():
-    yaml.BaseLoader = yaml.PyBaseLoader
-    yaml.SafeLoader = yaml.PySafeLoader
-    yaml.Loader = yaml.PyLoader
-    yaml.BaseDumper = yaml.PyBaseDumper
-    yaml.SafeDumper = yaml.PySafeDumper
-    yaml.Dumper = yaml.PyDumper
-    yaml.scan = old_scan
-    yaml.parse = old_parse
-    yaml.compose = old_compose
-    yaml.compose_all = old_compose_all
-    yaml.load = old_load
-    yaml.load_all = old_load_all
-    yaml.safe_load = old_safe_load
-    yaml.safe_load_all = old_safe_load_all
-    yaml.emit = old_emit
-    yaml.serialize = old_serialize
-    yaml.serialize_all = old_serialize_all
-    yaml.dump = old_dump
-    yaml.dump_all = old_dump_all
-    yaml.safe_dump = old_safe_dump
-    yaml.safe_dump_all = old_safe_dump_all
-
-def test_c_version(verbose=False):
-    if verbose:
-        print(_yaml.get_version())
-        print(_yaml.get_version_string())
-    assert ("%s.%s.%s" % _yaml.get_version()) == _yaml.get_version_string(),    \
-            (_yaml.get_version(), _yaml.get_version_string())
-
-def _compare_scanners(py_data, c_data, verbose):
-    py_tokens = list(yaml.scan(py_data, Loader=yaml.PyLoader))
-    c_tokens = []
-    try:
-        for token in yaml.scan(c_data, Loader=yaml.CLoader):
-            c_tokens.append(token)
-        assert len(py_tokens) == len(c_tokens), (len(py_tokens), len(c_tokens))
-        for py_token, c_token in zip(py_tokens, c_tokens):
-            assert py_token.__class__ == c_token.__class__, (py_token, c_token)
-            if hasattr(py_token, 'value'):
-                assert py_token.value == c_token.value, (py_token, c_token)
-            if isinstance(py_token, yaml.StreamEndToken):
-                continue
-            py_start = (py_token.start_mark.index, py_token.start_mark.line, py_token.start_mark.column)
-            py_end = (py_token.end_mark.index, py_token.end_mark.line, py_token.end_mark.column)
-            c_start = (c_token.start_mark.index, c_token.start_mark.line, c_token.start_mark.column)
-            c_end = (c_token.end_mark.index, c_token.end_mark.line, c_token.end_mark.column)
-            assert py_start == c_start, (py_start, c_start)
-            assert py_end == c_end, (py_end, c_end)
-    finally:
-        if verbose:
-            print("PY_TOKENS:")
-            pprint.pprint(py_tokens)
-            print("C_TOKENS:")
-            pprint.pprint(c_tokens)
-
-def test_c_scanner(data_filename, canonical_filename, verbose=False):
-    _compare_scanners(open(data_filename, 'rb'),
-            open(data_filename, 'rb'), verbose)
-    _compare_scanners(open(data_filename, 'rb').read(),
-            open(data_filename, 'rb').read(), verbose)
-    _compare_scanners(open(canonical_filename, 'rb'),
-            open(canonical_filename, 'rb'), verbose)
-    _compare_scanners(open(canonical_filename, 'rb').read(),
-            open(canonical_filename, 'rb').read(), verbose)
-
-test_c_scanner.unittest = ['.data', '.canonical']
-test_c_scanner.skip = ['.skip-ext']
-
-def _compare_parsers(py_data, c_data, verbose):
-    py_events = list(yaml.parse(py_data, Loader=yaml.PyLoader))
-    c_events = []
-    try:
-        for event in yaml.parse(c_data, Loader=yaml.CLoader):
-            c_events.append(event)
-        assert len(py_events) == len(c_events), (len(py_events), len(c_events))
-        for py_event, c_event in zip(py_events, c_events):
-            for attribute in ['__class__', 'anchor', 'tag', 'implicit',
-                                'value', 'explicit', 'version', 'tags']:
-                py_value = getattr(py_event, attribute, None)
-                c_value = getattr(c_event, attribute, None)
-                assert py_value == c_value, (py_event, c_event, attribute)
-    finally:
-        if verbose:
-            print("PY_EVENTS:")
-            pprint.pprint(py_events)
-            print("C_EVENTS:")
-            pprint.pprint(c_events)
-
-def test_c_parser(data_filename, canonical_filename, verbose=False):
-    _compare_parsers(open(data_filename, 'rb'),
-            open(data_filename, 'rb'), verbose)
-    _compare_parsers(open(data_filename, 'rb').read(),
-            open(data_filename, 'rb').read(), verbose)
-    _compare_parsers(open(canonical_filename, 'rb'),
-            open(canonical_filename, 'rb'), verbose)
-    _compare_parsers(open(canonical_filename, 'rb').read(),
-            open(canonical_filename, 'rb').read(), verbose)
-
-test_c_parser.unittest = ['.data', '.canonical']
-test_c_parser.skip = ['.skip-ext']
-
-def _compare_emitters(data, verbose):
-    events = list(yaml.parse(data, Loader=yaml.PyLoader))
-    c_data = yaml.emit(events, Dumper=yaml.CDumper)
-    if verbose:
-        print(c_data)
-    py_events = list(yaml.parse(c_data, Loader=yaml.PyLoader))
-    c_events = list(yaml.parse(c_data, Loader=yaml.CLoader))
-    try:
-        assert len(events) == len(py_events), (len(events), len(py_events))
-        assert len(events) == len(c_events), (len(events), len(c_events))
-        for event, py_event, c_event in zip(events, py_events, c_events):
-            for attribute in ['__class__', 'anchor', 'tag', 'implicit',
-                                'value', 'explicit', 'version', 'tags']:
-                value = getattr(event, attribute, None)
-                py_value = getattr(py_event, attribute, None)
-                c_value = getattr(c_event, attribute, None)
-                if attribute == 'tag' and value in [None, '!'] \
-                        and py_value in [None, '!'] and c_value in [None, '!']:
-                    continue
-                if attribute == 'explicit' and (py_value or c_value):
-                    continue
-                assert value == py_value, (event, py_event, attribute)
-                assert value == c_value, (event, c_event, attribute)
-    finally:
-        if verbose:
-            print("EVENTS:")
-            pprint.pprint(events)
-            print("PY_EVENTS:")
-            pprint.pprint(py_events)
-            print("C_EVENTS:")
-            pprint.pprint(c_events)
-
-def test_c_emitter(data_filename, canonical_filename, verbose=False):
-    _compare_emitters(open(data_filename, 'rb').read(), verbose)
-    _compare_emitters(open(canonical_filename, 'rb').read(), verbose)
-
-test_c_emitter.unittest = ['.data', '.canonical']
-test_c_emitter.skip = ['.skip-ext']
-
-def wrap_ext_function(function):
-    def wrapper(*args, **kwds):
-        _set_up()
-        try:
-            function(*args, **kwds)
-        finally:
-            _tear_down()
-    wrapper.__name__ = '%s_ext' % function.__name__
-    wrapper.unittest = function.unittest
-    wrapper.skip = getattr(function, 'skip', [])+['.skip-ext']
-    return wrapper
-
-def wrap_ext(collections):
-    functions = []
-    if not isinstance(collections, list):
-        collections = [collections]
-    for collection in collections:
-        if not isinstance(collection, dict):
-            collection = vars(collection)
-        for key in sorted(collection):
-            value = collection[key]
-            if isinstance(value, types.FunctionType) and hasattr(value, 'unittest'):
-                functions.append(wrap_ext_function(value))
-    for function in functions:
-        assert function.__name__ not in globals()
-        globals()[function.__name__] = function
-
-import test_tokens, test_structure, test_errors, test_resolver, test_constructor,   \
-        test_emitter, test_representer, test_recursive, test_input_output
-wrap_ext([test_tokens, test_structure, test_errors, test_resolver, test_constructor,
-        test_emitter, test_representer, test_recursive, test_input_output])
-
-if __name__ == '__main__':
-    import test_appliance
-    test_appliance.run(globals())
-
diff --git a/tox.ini b/tox.ini
index 517dbc3..d736a6c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,8 +1,9 @@
 [tox]
-envlist = py26,py27,pypy,py33,py34,py35,py36
+envlist = pypy3,py36,py37,py38,py39,py310
 
 [testenv]
 deps =
     Cython
 commands =
     python setup.py test
+passenv = PYYAML_TEST_GROUP
diff --git a/tests/data/emitting-unacceptable-unicode-character-bug-py2.skip-ext b/yaml/__init__.pxd
similarity index 100%
copy from tests/data/emitting-unacceptable-unicode-character-bug-py2.skip-ext
copy to yaml/__init__.pxd
diff --git a/yaml/_yaml.h b/yaml/_yaml.h
new file mode 100644
index 0000000..e3984c4
--- /dev/null
+++ b/yaml/_yaml.h
@@ -0,0 +1,13 @@
+
+#include <yaml.h>
+
+#define PyUnicode_FromYamlString(s) PyUnicode_FromString((const char *)(void *)(s))
+#define PyBytes_AS_Yaml_STRING(s) ((yaml_char_t *)PyBytes_AS_STRING(s))
+
+#ifdef _MSC_VER	/* MS Visual C++ 6.0 */
+#if _MSC_VER == 1200
+
+#define PyLong_FromUnsignedLongLong(z)	PyInt_FromLong(i)
+
+#endif
+#endif
diff --git a/ext/_yaml.pxd b/yaml/_yaml.pxd
similarity index 89%
rename from ext/_yaml.pxd
rename to yaml/_yaml.pxd
index 7937c9d..713244d 100644
--- a/ext/_yaml.pxd
+++ b/yaml/_yaml.pxd
@@ -2,18 +2,25 @@
 cdef extern from "_yaml.h":
 
     void malloc(int l)
-    void memcpy(char *d, char *s, int l)
+    void memcpy(void *d, void *s, int l)
     int strlen(char *s)
     int PyString_CheckExact(object o)
     int PyUnicode_CheckExact(object o)
     char *PyString_AS_STRING(object o)
-    int PyString_GET_SIZE(object o)
-    object PyString_FromStringAndSize(char *v, int l)
     object PyUnicode_FromString(char *u)
     object PyUnicode_DecodeUTF8(char *u, int s, char *e)
     object PyUnicode_AsUTF8String(object o)
     int PY_MAJOR_VERSION
 
+    ctypedef unsigned char yaml_char_t
+
+    object PyUnicode_FromYamlString(void *u)
+    yaml_char_t *PyBytes_AS_Yaml_STRING(object o)
+    const char *PyBytes_AS_STRING(object o)
+    int PyBytes_CheckExact(object o)
+    int PyBytes_GET_SIZE(object o)
+    object PyBytes_FromStringAndSize(char *v, int l)
+
     ctypedef enum:
         SIZEOF_VOID_P
     ctypedef enum yaml_encoding_t:
@@ -85,10 +92,10 @@
         YAML_MAPPING_START_EVENT
         YAML_MAPPING_END_EVENT
 
-    ctypedef int yaml_read_handler_t(void *data, char *buffer,
+    ctypedef int yaml_read_handler_t(void *data, unsigned char *buffer,
             size_t size, size_t *size_read) except 0
 
-    ctypedef int yaml_write_handler_t(void *data, char *buffer,
+    ctypedef int yaml_write_handler_t(void *data, unsigned char *buffer,
             size_t size) except 0
 
     ctypedef struct yaml_mark_t:
@@ -99,8 +106,8 @@
         int major
         int minor
     ctypedef struct yaml_tag_directive_t:
-        char *handle
-        char *prefix
+        yaml_char_t *handle
+        yaml_char_t *prefix
 
     ctypedef struct _yaml_token_stream_start_data_t:
         yaml_encoding_t encoding
@@ -208,23 +215,23 @@
             int implicit)
     int yaml_document_end_event_initialize(yaml_event_t *event,
             int implicit)
-    int yaml_alias_event_initialize(yaml_event_t *event, char *anchor)
+    int yaml_alias_event_initialize(yaml_event_t *event, yaml_char_t *anchor)
     int yaml_scalar_event_initialize(yaml_event_t *event,
-            char *anchor, char *tag, char *value, size_t length,
+            yaml_char_t *anchor, yaml_char_t *tag, yaml_char_t *value, int length,
             int plain_implicit, int quoted_implicit,
             yaml_scalar_style_t style)
     int yaml_sequence_start_event_initialize(yaml_event_t *event,
-            char *anchor, char *tag, int implicit, yaml_sequence_style_t style)
+            yaml_char_t *anchor, yaml_char_t *tag, int implicit, yaml_sequence_style_t style)
     int yaml_sequence_end_event_initialize(yaml_event_t *event)
     int yaml_mapping_start_event_initialize(yaml_event_t *event,
-            char *anchor, char *tag, int implicit, yaml_mapping_style_t style)
+            yaml_char_t *anchor, yaml_char_t *tag, int implicit, yaml_mapping_style_t style)
     int yaml_mapping_end_event_initialize(yaml_event_t *event)
     void yaml_event_delete(yaml_event_t *event)
 
     int yaml_parser_initialize(yaml_parser_t *parser)
     void yaml_parser_delete(yaml_parser_t *parser)
     void yaml_parser_set_input_string(yaml_parser_t *parser,
-            char *input, size_t size)
+            const unsigned char *input, size_t size)
     void yaml_parser_set_input(yaml_parser_t *parser,
             yaml_read_handler_t *handler, void *data)
     void yaml_parser_set_encoding(yaml_parser_t *parser,
diff --git a/ext/_yaml.pyx b/yaml/_yaml.pyx
similarity index 79%
rename from ext/_yaml.pyx
rename to yaml/_yaml.pyx
index b2f409c..e3e93e2 100644
--- a/ext/_yaml.pyx
+++ b/yaml/_yaml.pyx
@@ -2,12 +2,9 @@
 import yaml
 
 def get_version_string():
-    cdef char *value
+    cdef const char *value
     value = yaml_get_version_string()
-    if PY_MAJOR_VERSION < 3:
-        return value
-    else:
-        return PyUnicode_FromString(value)
+    return PyUnicode_FromString(value)
 
 def get_version():
     cdef int major, minor, patch
@@ -63,13 +60,13 @@
 
 cdef class Mark:
     cdef readonly object name
-    cdef readonly int index
-    cdef readonly int line
-    cdef readonly int column
+    cdef readonly size_t index
+    cdef readonly size_t line
+    cdef readonly size_t column
     cdef readonly buffer
     cdef readonly pointer
 
-    def __init__(self, object name, int index, int line, int column,
+    def __init__(self, object name, size_t index, size_t line, size_t column,
             object buffer, object pointer):
         self.name = name
         self.index = index
@@ -275,10 +272,7 @@
             try:
                 self.stream_name = stream.name
             except AttributeError:
-                if PY_MAJOR_VERSION < 3:
-                    self.stream_name = '<file>'
-                else:
-                    self.stream_name = u'<file>'
+                self.stream_name = u'<file>'
             self.stream_cache = None
             self.stream_cache_len = 0
             self.stream_cache_pos = 0
@@ -286,23 +280,14 @@
         else:
             if PyUnicode_CheckExact(stream) != 0:
                 stream = PyUnicode_AsUTF8String(stream)
-                if PY_MAJOR_VERSION < 3:
-                    self.stream_name = '<unicode string>'
-                else:
-                    self.stream_name = u'<unicode string>'
+                self.stream_name = u'<unicode string>'
                 self.unicode_source = 1
             else:
-                if PY_MAJOR_VERSION < 3:
-                    self.stream_name = '<byte string>'
-                else:
-                    self.stream_name = u'<byte string>'
-            if PyString_CheckExact(stream) == 0:
-                if PY_MAJOR_VERSION < 3:
-                    raise TypeError("a string or stream input is required")
-                else:
-                    raise TypeError(u"a string or stream input is required")
+                self.stream_name = u'<byte string>'
+            if PyBytes_CheckExact(stream) == 0:
+                raise TypeError(u"a string or stream input is required")
             self.stream = stream
-            yaml_parser_set_input_string(&self.parser, PyString_AS_STRING(stream), PyString_GET_SIZE(stream))
+            yaml_parser_set_input_string(&self.parser, PyBytes_AS_Yaml_STRING(stream), PyBytes_GET_SIZE(stream))
         self.current_token = None
         self.current_event = None
         self.anchors = {}
@@ -318,12 +303,8 @@
         if self.parser.error == YAML_MEMORY_ERROR:
             return MemoryError
         elif self.parser.error == YAML_READER_ERROR:
-            if PY_MAJOR_VERSION < 3:
-                return ReaderError(self.stream_name, self.parser.problem_offset,
-                        self.parser.problem_value, '?', self.parser.problem)
-            else:
-                return ReaderError(self.stream_name, self.parser.problem_offset,
-                        self.parser.problem_value, u'?', PyUnicode_FromString(self.parser.problem))
+            return ReaderError(self.stream_name, self.parser.problem_offset,
+                    self.parser.problem_value, u'?', PyUnicode_FromString(self.parser.problem))
         elif self.parser.error == YAML_SCANNER_ERROR    \
                 or self.parser.error == YAML_PARSER_ERROR:
             context_mark = None
@@ -340,22 +321,13 @@
                         self.parser.problem_mark.column, None, None)
             context = None
             if self.parser.context != NULL:
-                if PY_MAJOR_VERSION < 3:
-                    context = self.parser.context
-                else:
-                    context = PyUnicode_FromString(self.parser.context)
-            if PY_MAJOR_VERSION < 3:
-                problem = self.parser.problem
-            else:
-                problem = PyUnicode_FromString(self.parser.problem)
+                context = PyUnicode_FromString(self.parser.context)
+            problem = PyUnicode_FromString(self.parser.problem)
             if self.parser.error == YAML_SCANNER_ERROR:
                 return ScannerError(context, context_mark, problem, problem_mark)
             else:
                 return ParserError(context, context_mark, problem, problem_mark)
-        if PY_MAJOR_VERSION < 3:
-            raise ValueError("no parser error")
-        else:
-            raise ValueError(u"no parser error")
+        raise ValueError(u"no parser error")
 
     def raw_scan(self):
         cdef yaml_token_t token
@@ -414,8 +386,8 @@
                         token.data.version_directive.minor),
                     start_mark, end_mark)
         elif token.type == YAML_TAG_DIRECTIVE_TOKEN:
-            handle = PyUnicode_FromString(token.data.tag_directive.handle)
-            prefix = PyUnicode_FromString(token.data.tag_directive.prefix)
+            handle = PyUnicode_FromYamlString(token.data.tag_directive.handle)
+            prefix = PyUnicode_FromYamlString(token.data.tag_directive.prefix)
             return DirectiveToken(u"TAG", (handle, prefix),
                     start_mark, end_mark)
         elif token.type == YAML_DOCUMENT_START_TOKEN:
@@ -445,19 +417,19 @@
         elif token.type == YAML_VALUE_TOKEN:
             return ValueToken(start_mark, end_mark)
         elif token.type == YAML_ALIAS_TOKEN:
-            value = PyUnicode_FromString(token.data.alias.value)
+            value = PyUnicode_FromYamlString(token.data.alias.value)
             return AliasToken(value, start_mark, end_mark)
         elif token.type == YAML_ANCHOR_TOKEN:
-            value = PyUnicode_FromString(token.data.anchor.value)
+            value = PyUnicode_FromYamlString(token.data.anchor.value)
             return AnchorToken(value, start_mark, end_mark)
         elif token.type == YAML_TAG_TOKEN:
-            handle = PyUnicode_FromString(token.data.tag.handle)
-            suffix = PyUnicode_FromString(token.data.tag.suffix)
+            handle = PyUnicode_FromYamlString(token.data.tag.handle)
+            suffix = PyUnicode_FromYamlString(token.data.tag.suffix)
             if not handle:
                 handle = None
             return TagToken((handle, suffix), start_mark, end_mark)
         elif token.type == YAML_SCALAR_TOKEN:
-            value = PyUnicode_DecodeUTF8(token.data.scalar.value,
+            value = PyUnicode_DecodeUTF8(<char *>token.data.scalar.value,
                     token.data.scalar.length, 'strict')
             plain = False
             style = None
@@ -475,10 +447,7 @@
             return ScalarToken(value, plain,
                     start_mark, end_mark, style)
         else:
-            if PY_MAJOR_VERSION < 3:
-                raise ValueError("unknown token type")
-            else:
-                raise ValueError(u"unknown token type")
+            raise ValueError(u"unknown token type")
 
     def get_token(self):
         if self.current_token is not None:
@@ -571,8 +540,8 @@
                 tags = {}
                 tag_directive = event.data.document_start.tag_directives.start
                 while tag_directive != event.data.document_start.tag_directives.end:
-                    handle = PyUnicode_FromString(tag_directive.handle)
-                    prefix = PyUnicode_FromString(tag_directive.prefix)
+                    handle = PyUnicode_FromYamlString(tag_directive.handle)
+                    prefix = PyUnicode_FromYamlString(tag_directive.prefix)
                     tags[handle] = prefix
                     tag_directive = tag_directive+1
             return DocumentStartEvent(start_mark, end_mark,
@@ -583,16 +552,16 @@
                 explicit = True
             return DocumentEndEvent(start_mark, end_mark, explicit)
         elif event.type == YAML_ALIAS_EVENT:
-            anchor = PyUnicode_FromString(event.data.alias.anchor)
+            anchor = PyUnicode_FromYamlString(event.data.alias.anchor)
             return AliasEvent(anchor, start_mark, end_mark)
         elif event.type == YAML_SCALAR_EVENT:
             anchor = None
             if event.data.scalar.anchor != NULL:
-                anchor = PyUnicode_FromString(event.data.scalar.anchor)
+                anchor = PyUnicode_FromYamlString(event.data.scalar.anchor)
             tag = None
             if event.data.scalar.tag != NULL:
-                tag = PyUnicode_FromString(event.data.scalar.tag)
-            value = PyUnicode_DecodeUTF8(event.data.scalar.value,
+                tag = PyUnicode_FromYamlString(event.data.scalar.tag)
+            value = PyUnicode_DecodeUTF8(<char *>event.data.scalar.value,
                     event.data.scalar.length, 'strict')
             plain_implicit = False
             if event.data.scalar.plain_implicit == 1:
@@ -617,10 +586,10 @@
         elif event.type == YAML_SEQUENCE_START_EVENT:
             anchor = None
             if event.data.sequence_start.anchor != NULL:
-                anchor = PyUnicode_FromString(event.data.sequence_start.anchor)
+                anchor = PyUnicode_FromYamlString(event.data.sequence_start.anchor)
             tag = None
             if event.data.sequence_start.tag != NULL:
-                tag = PyUnicode_FromString(event.data.sequence_start.tag)
+                tag = PyUnicode_FromYamlString(event.data.sequence_start.tag)
             implicit = False
             if event.data.sequence_start.implicit == 1:
                 implicit = True
@@ -634,10 +603,10 @@
         elif event.type == YAML_MAPPING_START_EVENT:
             anchor = None
             if event.data.mapping_start.anchor != NULL:
-                anchor = PyUnicode_FromString(event.data.mapping_start.anchor)
+                anchor = PyUnicode_FromYamlString(event.data.mapping_start.anchor)
             tag = None
             if event.data.mapping_start.tag != NULL:
-                tag = PyUnicode_FromString(event.data.mapping_start.tag)
+                tag = PyUnicode_FromYamlString(event.data.mapping_start.tag)
             implicit = False
             if event.data.mapping_start.implicit == 1:
                 implicit = True
@@ -653,10 +622,7 @@
         elif event.type == YAML_MAPPING_END_EVENT:
             return MappingEndEvent(start_mark, end_mark)
         else:
-            if PY_MAJOR_VERSION < 3:
-                raise ValueError("unknown event type")
-            else:
-                raise ValueError(u"unknown event type")
+            raise ValueError(u"unknown event type")
 
     def get_event(self):
         if self.current_event is not None:
@@ -712,12 +678,8 @@
                     self.parsed_event.start_mark.line,
                     self.parsed_event.start_mark.column,
                     None, None)
-            if PY_MAJOR_VERSION < 3:
-                raise ComposerError("expected a single document in the stream",
-                        document.start_mark, "but found another document", mark)
-            else:
-                raise ComposerError(u"expected a single document in the stream",
-                        document.start_mark, u"but found another document", mark)
+            raise ComposerError(u"expected a single document in the stream",
+                    document.start_mark, u"but found another document", mark)
         return document
 
     cdef object _compose_document(self):
@@ -731,29 +693,26 @@
     cdef object _compose_node(self, object parent, object index):
         self._parse_next_event()
         if self.parsed_event.type == YAML_ALIAS_EVENT:
-            anchor = PyUnicode_FromString(self.parsed_event.data.alias.anchor)
+            anchor = PyUnicode_FromYamlString(self.parsed_event.data.alias.anchor)
             if anchor not in self.anchors:
                 mark = Mark(self.stream_name,
                         self.parsed_event.start_mark.index,
                         self.parsed_event.start_mark.line,
                         self.parsed_event.start_mark.column,
                         None, None)
-                if PY_MAJOR_VERSION < 3:
-                    raise ComposerError(None, None, "found undefined alias", mark)
-                else:
-                    raise ComposerError(None, None, u"found undefined alias", mark)
+                raise ComposerError(None, None, u"found undefined alias", mark)
             yaml_event_delete(&self.parsed_event)
             return self.anchors[anchor]
         anchor = None
         if self.parsed_event.type == YAML_SCALAR_EVENT  \
                 and self.parsed_event.data.scalar.anchor != NULL:
-            anchor = PyUnicode_FromString(self.parsed_event.data.scalar.anchor)
+            anchor = PyUnicode_FromYamlString(self.parsed_event.data.scalar.anchor)
         elif self.parsed_event.type == YAML_SEQUENCE_START_EVENT    \
                 and self.parsed_event.data.sequence_start.anchor != NULL:
-            anchor = PyUnicode_FromString(self.parsed_event.data.sequence_start.anchor)
+            anchor = PyUnicode_FromYamlString(self.parsed_event.data.sequence_start.anchor)
         elif self.parsed_event.type == YAML_MAPPING_START_EVENT    \
                 and self.parsed_event.data.mapping_start.anchor != NULL:
-            anchor = PyUnicode_FromString(self.parsed_event.data.mapping_start.anchor)
+            anchor = PyUnicode_FromYamlString(self.parsed_event.data.mapping_start.anchor)
         if anchor is not None:
             if anchor in self.anchors:
                 mark = Mark(self.stream_name,
@@ -761,12 +720,8 @@
                         self.parsed_event.start_mark.line,
                         self.parsed_event.start_mark.column,
                         None, None)
-                if PY_MAJOR_VERSION < 3:
-                    raise ComposerError("found duplicate anchor; first occurrence",
-                            self.anchors[anchor].start_mark, "second occurrence", mark)
-                else:
-                    raise ComposerError(u"found duplicate anchor; first occurrence",
-                            self.anchors[anchor].start_mark, u"second occurrence", mark)
+                raise ComposerError(u"found duplicate anchor; first occurrence",
+                        self.anchors[anchor].start_mark, u"second occurrence", mark)
         self.descend_resolver(parent, index)
         if self.parsed_event.type == YAML_SCALAR_EVENT:
             node = self._compose_scalar_node(anchor)
@@ -788,7 +743,7 @@
                 self.parsed_event.end_mark.line,
                 self.parsed_event.end_mark.column,
                 None, None)
-        value = PyUnicode_DecodeUTF8(self.parsed_event.data.scalar.value,
+        value = PyUnicode_DecodeUTF8(<char *>self.parsed_event.data.scalar.value,
                 self.parsed_event.data.scalar.length, 'strict')
         plain_implicit = False
         if self.parsed_event.data.scalar.plain_implicit == 1:
@@ -801,7 +756,7 @@
                         and self.parsed_event.data.scalar.tag[1] == c'\0'):
             tag = self.resolve(ScalarNode, value, (plain_implicit, quoted_implicit))
         else:
-            tag = PyUnicode_FromString(self.parsed_event.data.scalar.tag)
+            tag = PyUnicode_FromYamlString(self.parsed_event.data.scalar.tag)
         style = None
         if self.parsed_event.data.scalar.style == YAML_PLAIN_SCALAR_STYLE:
             style = u''
@@ -834,7 +789,7 @@
                         and self.parsed_event.data.sequence_start.tag[1] == c'\0'):
             tag = self.resolve(SequenceNode, None, implicit)
         else:
-            tag = PyUnicode_FromString(self.parsed_event.data.sequence_start.tag)
+            tag = PyUnicode_FromYamlString(self.parsed_event.data.sequence_start.tag)
         flow_style = None
         if self.parsed_event.data.sequence_start.style == YAML_FLOW_SEQUENCE_STYLE:
             flow_style = True
@@ -873,7 +828,7 @@
                         and self.parsed_event.data.mapping_start.tag[1] == c'\0'):
             tag = self.resolve(MappingNode, None, implicit)
         else:
-            tag = PyUnicode_FromString(self.parsed_event.data.mapping_start.tag)
+            tag = PyUnicode_FromYamlString(self.parsed_event.data.mapping_start.tag)
         flow_style = None
         if self.parsed_event.data.mapping_start.style == YAML_FLOW_MAPPING_STYLE:
             flow_style = True
@@ -905,7 +860,7 @@
                 raise error
         return 1
 
-cdef int input_handler(void *data, char *buffer, size_t size, size_t *read) except 0:
+cdef int input_handler(void *data, unsigned char *buffer, size_t size, size_t *read) except 0:
     cdef CParser parser
     parser = <CParser>data
     if parser.stream_cache is None:
@@ -913,18 +868,15 @@
         if PyUnicode_CheckExact(value) != 0:
             value = PyUnicode_AsUTF8String(value)
             parser.unicode_source = 1
-        if PyString_CheckExact(value) == 0:
-            if PY_MAJOR_VERSION < 3:
-                raise TypeError("a string value is expected")
-            else:
-                raise TypeError(u"a string value is expected")
+        if PyBytes_CheckExact(value) == 0:
+            raise TypeError(u"a string value is expected")
         parser.stream_cache = value
         parser.stream_cache_pos = 0
-        parser.stream_cache_len = PyString_GET_SIZE(value)
-    if (parser.stream_cache_len - parser.stream_cache_pos) < size:
+        parser.stream_cache_len = PyBytes_GET_SIZE(value)
+    if (parser.stream_cache_len - parser.stream_cache_pos) < <int>size:
         size = parser.stream_cache_len - parser.stream_cache_pos
     if size > 0:
-        memcpy(buffer, PyString_AS_STRING(parser.stream_cache)
+        memcpy(buffer, PyBytes_AS_STRING(parser.stream_cache)
                             + parser.stream_cache_pos, size)
     read[0] = size
     parser.stream_cache_pos += size
@@ -957,12 +909,8 @@
             raise MemoryError
         self.stream = stream
         self.dump_unicode = 0
-        if PY_MAJOR_VERSION < 3:
-            if getattr3(stream, 'encoding', None):
-                self.dump_unicode = 1
-        else:
-            if hasattr(stream, u'encoding'):
-                self.dump_unicode = 1
+        if hasattr(stream, u'encoding'):
+            self.dump_unicode = 1
         self.use_encoding = encoding
         yaml_emitter_set_output(&self.emitter, output_handler, <void *>self)    
         if canonical:
@@ -1003,15 +951,9 @@
         if self.emitter.error == YAML_MEMORY_ERROR:
             return MemoryError
         elif self.emitter.error == YAML_EMITTER_ERROR:
-            if PY_MAJOR_VERSION < 3:
-                problem = self.emitter.problem
-            else:
-                problem = PyUnicode_FromString(self.emitter.problem)
+            problem = PyUnicode_FromString(self.emitter.problem)
             return EmitterError(problem)
-        if PY_MAJOR_VERSION < 3:
-            raise ValueError("no emitter error")
-        else:
-            raise ValueError(u"no emitter error")
+        raise ValueError(u"no emitter error")
 
     cdef int _object_to_event(self, object event_object, yaml_event_t *event) except 0:
         cdef yaml_encoding_t encoding
@@ -1023,9 +965,9 @@
         cdef int implicit
         cdef int plain_implicit
         cdef int quoted_implicit
-        cdef char *anchor
-        cdef char *tag
-        cdef char *value
+        cdef yaml_char_t *anchor
+        cdef yaml_char_t *tag
+        cdef yaml_char_t *value
         cdef int length
         cdef yaml_scalar_style_t scalar_style
         cdef yaml_sequence_style_t sequence_style
@@ -1054,10 +996,7 @@
             tag_directives_end = NULL
             if event_object.tags:
                 if len(event_object.tags) > 128:
-                    if PY_MAJOR_VERSION < 3:
-                        raise ValueError("too many tags")
-                    else:
-                        raise ValueError(u"too many tags")
+                    raise ValueError(u"too many tags")
                 tag_directives_start = tag_directives_value
                 tag_directives_end = tag_directives_value
                 cache = []
@@ -1066,21 +1005,15 @@
                     if PyUnicode_CheckExact(handle):
                         handle = PyUnicode_AsUTF8String(handle)
                         cache.append(handle)
-                    if not PyString_CheckExact(handle):
-                        if PY_MAJOR_VERSION < 3:
-                            raise TypeError("tag handle must be a string")
-                        else:
-                            raise TypeError(u"tag handle must be a string")
-                    tag_directives_end.handle = PyString_AS_STRING(handle)
+                    if not PyBytes_CheckExact(handle):
+                        raise TypeError(u"tag handle must be a string")
+                    tag_directives_end.handle = PyBytes_AS_Yaml_STRING(handle)
                     if PyUnicode_CheckExact(prefix):
                         prefix = PyUnicode_AsUTF8String(prefix)
                         cache.append(prefix)
-                    if not PyString_CheckExact(prefix):
-                        if PY_MAJOR_VERSION < 3:
-                            raise TypeError("tag prefix must be a string")
-                        else:
-                            raise TypeError(u"tag prefix must be a string")
-                    tag_directives_end.prefix = PyString_AS_STRING(prefix)
+                    if not PyBytes_CheckExact(prefix):
+                        raise TypeError(u"tag prefix must be a string")
+                    tag_directives_end.prefix = PyBytes_AS_Yaml_STRING(prefix)
                     tag_directives_end = tag_directives_end+1
             implicit = 1
             if event_object.explicit:
@@ -1098,12 +1031,9 @@
             anchor_object = event_object.anchor
             if PyUnicode_CheckExact(anchor_object):
                 anchor_object = PyUnicode_AsUTF8String(anchor_object)
-            if not PyString_CheckExact(anchor_object):
-                if PY_MAJOR_VERSION < 3:
-                    raise TypeError("anchor must be a string")
-                else:
-                    raise TypeError(u"anchor must be a string")
-            anchor = PyString_AS_STRING(anchor_object)
+            if not PyBytes_CheckExact(anchor_object):
+                raise TypeError(u"anchor must be a string")
+            anchor = PyBytes_AS_Yaml_STRING(anchor_object)
             if yaml_alias_event_initialize(event, anchor) == 0:
                 raise MemoryError
         elif event_class is ScalarEvent:
@@ -1112,33 +1042,24 @@
             if anchor_object is not None:
                 if PyUnicode_CheckExact(anchor_object):
                     anchor_object = PyUnicode_AsUTF8String(anchor_object)
-                if not PyString_CheckExact(anchor_object):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("anchor must be a string")
-                    else:
-                        raise TypeError(u"anchor must be a string")
-                anchor = PyString_AS_STRING(anchor_object)
+                if not PyBytes_CheckExact(anchor_object):
+                    raise TypeError(u"anchor must be a string")
+                anchor = PyBytes_AS_Yaml_STRING(anchor_object)
             tag = NULL
             tag_object = event_object.tag
             if tag_object is not None:
                 if PyUnicode_CheckExact(tag_object):
                     tag_object = PyUnicode_AsUTF8String(tag_object)
-                if not PyString_CheckExact(tag_object):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("tag must be a string")
-                    else:
-                        raise TypeError(u"tag must be a string")
-                tag = PyString_AS_STRING(tag_object)
+                if not PyBytes_CheckExact(tag_object):
+                    raise TypeError(u"tag must be a string")
+                tag = PyBytes_AS_Yaml_STRING(tag_object)
             value_object = event_object.value
             if PyUnicode_CheckExact(value_object):
                 value_object = PyUnicode_AsUTF8String(value_object)
-            if not PyString_CheckExact(value_object):
-                if PY_MAJOR_VERSION < 3:
-                    raise TypeError("value must be a string")
-                else:
-                    raise TypeError(u"value must be a string")
-            value = PyString_AS_STRING(value_object)
-            length = PyString_GET_SIZE(value_object)
+            if not PyBytes_CheckExact(value_object):
+                raise TypeError(u"value must be a string")
+            value = PyBytes_AS_Yaml_STRING(value_object)
+            length = PyBytes_GET_SIZE(value_object)
             plain_implicit = 0
             quoted_implicit = 0
             if event_object.implicit is not None:
@@ -1163,23 +1084,17 @@
             if anchor_object is not None:
                 if PyUnicode_CheckExact(anchor_object):
                     anchor_object = PyUnicode_AsUTF8String(anchor_object)
-                if not PyString_CheckExact(anchor_object):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("anchor must be a string")
-                    else:
-                        raise TypeError(u"anchor must be a string")
-                anchor = PyString_AS_STRING(anchor_object)
+                if not PyBytes_CheckExact(anchor_object):
+                    raise TypeError(u"anchor must be a string")
+                anchor = PyBytes_AS_Yaml_STRING(anchor_object)
             tag = NULL
             tag_object = event_object.tag
             if tag_object is not None:
                 if PyUnicode_CheckExact(tag_object):
                     tag_object = PyUnicode_AsUTF8String(tag_object)
-                if not PyString_CheckExact(tag_object):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("tag must be a string")
-                    else:
-                        raise TypeError(u"tag must be a string")
-                tag = PyString_AS_STRING(tag_object)
+                if not PyBytes_CheckExact(tag_object):
+                    raise TypeError(u"tag must be a string")
+                tag = PyBytes_AS_Yaml_STRING(tag_object)
             implicit = 0
             if event_object.implicit:
                 implicit = 1
@@ -1195,23 +1110,17 @@
             if anchor_object is not None:
                 if PyUnicode_CheckExact(anchor_object):
                     anchor_object = PyUnicode_AsUTF8String(anchor_object)
-                if not PyString_CheckExact(anchor_object):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("anchor must be a string")
-                    else:
-                        raise TypeError(u"anchor must be a string")
-                anchor = PyString_AS_STRING(anchor_object)
+                if not PyBytes_CheckExact(anchor_object):
+                    raise TypeError(u"anchor must be a string")
+                anchor = PyBytes_AS_Yaml_STRING(anchor_object)
             tag = NULL
             tag_object = event_object.tag
             if tag_object is not None:
                 if PyUnicode_CheckExact(tag_object):
                     tag_object = PyUnicode_AsUTF8String(tag_object)
-                if not PyString_CheckExact(tag_object):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("tag must be a string")
-                    else:
-                        raise TypeError(u"tag must be a string")
-                tag = PyString_AS_STRING(tag_object)
+                if not PyBytes_CheckExact(tag_object):
+                    raise TypeError(u"tag must be a string")
+                tag = PyBytes_AS_Yaml_STRING(tag_object)
             implicit = 0
             if event_object.implicit:
                 implicit = 1
@@ -1226,10 +1135,7 @@
         elif event_class is MappingEndEvent:
             yaml_mapping_end_event_initialize(event)
         else:
-            if PY_MAJOR_VERSION < 3:
-                raise TypeError("invalid event %s" % event_object)
-            else:
-                raise TypeError(u"invalid event %s" % event_object)
+            raise TypeError(u"invalid event %s" % event_object)
         return 1
 
     def emit(self, event_object):
@@ -1259,23 +1165,14 @@
                 raise error
             self.closed = 0
         elif self.closed == 1:
-            if PY_MAJOR_VERSION < 3:
-                raise SerializerError("serializer is closed")
-            else:
-                raise SerializerError(u"serializer is closed")
+            raise SerializerError(u"serializer is closed")
         else:
-            if PY_MAJOR_VERSION < 3:
-                raise SerializerError("serializer is already opened")
-            else:
-                raise SerializerError(u"serializer is already opened")
+            raise SerializerError(u"serializer is already opened")
 
     def close(self):
         cdef yaml_event_t event
         if self.closed == -1:
-            if PY_MAJOR_VERSION < 3:
-                raise SerializerError("serializer is not opened")
-            else:
-                raise SerializerError(u"serializer is not opened")
+            raise SerializerError(u"serializer is not opened")
         elif self.closed == 0:
             yaml_stream_end_event_initialize(&event)
             if yaml_emitter_emit(&self.emitter, &event) == 0:
@@ -1291,15 +1188,9 @@
         cdef yaml_tag_directive_t *tag_directives_start
         cdef yaml_tag_directive_t *tag_directives_end
         if self.closed == -1:
-            if PY_MAJOR_VERSION < 3:
-                raise SerializerError("serializer is not opened")
-            else:
-                raise SerializerError(u"serializer is not opened")
+            raise SerializerError(u"serializer is not opened")
         elif self.closed == 1:
-            if PY_MAJOR_VERSION < 3:
-                raise SerializerError("serializer is closed")
-            else:
-                raise SerializerError(u"serializer is closed")
+            raise SerializerError(u"serializer is closed")
         cache = []
         version_directive = NULL
         if self.use_version:
@@ -1310,10 +1201,7 @@
         tag_directives_end = NULL
         if self.use_tags:
             if len(self.use_tags) > 128:
-                if PY_MAJOR_VERSION < 3:
-                    raise ValueError("too many tags")
-                else:
-                    raise ValueError(u"too many tags")
+                raise ValueError(u"too many tags")
             tag_directives_start = tag_directives_value
             tag_directives_end = tag_directives_value
             for handle in self.use_tags:
@@ -1321,21 +1209,15 @@
                 if PyUnicode_CheckExact(handle):
                     handle = PyUnicode_AsUTF8String(handle)
                     cache.append(handle)
-                if not PyString_CheckExact(handle):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("tag handle must be a string")
-                    else:
-                        raise TypeError(u"tag handle must be a string")
-                tag_directives_end.handle = PyString_AS_STRING(handle)
+                if not PyBytes_CheckExact(handle):
+                    raise TypeError(u"tag handle must be a string")
+                tag_directives_end.handle = PyBytes_AS_Yaml_STRING(handle)
                 if PyUnicode_CheckExact(prefix):
                     prefix = PyUnicode_AsUTF8String(prefix)
                     cache.append(prefix)
-                if not PyString_CheckExact(prefix):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("tag prefix must be a string")
-                    else:
-                        raise TypeError(u"tag prefix must be a string")
-                tag_directives_end.prefix = PyString_AS_STRING(prefix)
+                if not PyBytes_CheckExact(prefix):
+                    raise TypeError(u"tag prefix must be a string")
+                tag_directives_end.prefix = PyBytes_AS_Yaml_STRING(prefix)
                 tag_directives_end = tag_directives_end+1
         if yaml_document_start_event_initialize(&event, version_directive,
                 tag_directives_start, tag_directives_end,
@@ -1376,9 +1258,9 @@
         cdef int implicit
         cdef int plain_implicit
         cdef int quoted_implicit
-        cdef char *anchor
-        cdef char *tag
-        cdef char *value
+        cdef yaml_char_t *anchor
+        cdef yaml_char_t *tag
+        cdef yaml_char_t *value
         cdef int length
         cdef int item_index
         cdef yaml_scalar_style_t scalar_style
@@ -1389,12 +1271,9 @@
         if anchor_object is not None:
             if PyUnicode_CheckExact(anchor_object):
                 anchor_object = PyUnicode_AsUTF8String(anchor_object)
-            if not PyString_CheckExact(anchor_object):
-                if PY_MAJOR_VERSION < 3:
-                    raise TypeError("anchor must be a string")
-                else:
-                    raise TypeError(u"anchor must be a string")
-            anchor = PyString_AS_STRING(anchor_object)
+            if not PyBytes_CheckExact(anchor_object):
+                raise TypeError(u"anchor must be a string")
+            anchor = PyBytes_AS_Yaml_STRING(anchor_object)
         if node in self.serialized_nodes:
             if yaml_alias_event_initialize(&event, anchor) == 0:
                 raise MemoryError
@@ -1417,22 +1296,16 @@
                 if tag_object is not None:
                     if PyUnicode_CheckExact(tag_object):
                         tag_object = PyUnicode_AsUTF8String(tag_object)
-                    if not PyString_CheckExact(tag_object):
-                        if PY_MAJOR_VERSION < 3:
-                            raise TypeError("tag must be a string")
-                        else:
-                            raise TypeError(u"tag must be a string")
-                    tag = PyString_AS_STRING(tag_object)
+                    if not PyBytes_CheckExact(tag_object):
+                        raise TypeError(u"tag must be a string")
+                    tag = PyBytes_AS_Yaml_STRING(tag_object)
                 value_object = node.value
                 if PyUnicode_CheckExact(value_object):
                     value_object = PyUnicode_AsUTF8String(value_object)
-                if not PyString_CheckExact(value_object):
-                    if PY_MAJOR_VERSION < 3:
-                        raise TypeError("value must be a string")
-                    else:
-                        raise TypeError(u"value must be a string")
-                value = PyString_AS_STRING(value_object)
-                length = PyString_GET_SIZE(value_object)
+                if not PyBytes_CheckExact(value_object):
+                    raise TypeError(u"value must be a string")
+                value = PyBytes_AS_Yaml_STRING(value_object)
+                length = PyBytes_GET_SIZE(value_object)
                 style_object = node.style
                 scalar_style = YAML_PLAIN_SCALAR_STYLE
                 if style_object == "'" or style_object == u"'":
@@ -1458,12 +1331,9 @@
                 if tag_object is not None:
                     if PyUnicode_CheckExact(tag_object):
                         tag_object = PyUnicode_AsUTF8String(tag_object)
-                    if not PyString_CheckExact(tag_object):
-                        if PY_MAJOR_VERSION < 3:
-                            raise TypeError("tag must be a string")
-                        else:
-                            raise TypeError(u"tag must be a string")
-                    tag = PyString_AS_STRING(tag_object)
+                    if not PyBytes_CheckExact(tag_object):
+                        raise TypeError(u"tag must be a string")
+                    tag = PyBytes_AS_Yaml_STRING(tag_object)
                 sequence_style = YAML_BLOCK_SEQUENCE_STYLE
                 if node.flow_style:
                     sequence_style = YAML_FLOW_SEQUENCE_STYLE
@@ -1490,12 +1360,9 @@
                 if tag_object is not None:
                     if PyUnicode_CheckExact(tag_object):
                         tag_object = PyUnicode_AsUTF8String(tag_object)
-                    if not PyString_CheckExact(tag_object):
-                        if PY_MAJOR_VERSION < 3:
-                            raise TypeError("tag must be a string")
-                        else:
-                            raise TypeError(u"tag must be a string")
-                    tag = PyString_AS_STRING(tag_object)
+                    if not PyBytes_CheckExact(tag_object):
+                        raise TypeError(u"tag must be a string")
+                    tag = PyBytes_AS_Yaml_STRING(tag_object)
                 mapping_style = YAML_BLOCK_MAPPING_STYLE
                 if node.flow_style:
                     mapping_style = YAML_FLOW_MAPPING_STYLE
@@ -1515,11 +1382,13 @@
             self.ascend_resolver()
         return 1
 
-cdef int output_handler(void *data, char *buffer, size_t size) except 0:
+cdef int output_handler(void *data, unsigned char *bufferu, size_t size) except 0:
     cdef CEmitter emitter
+    cdef char *buffer
+    buffer = <char *>bufferu
     emitter = <CEmitter>data
     if emitter.dump_unicode == 0:
-        value = PyString_FromStringAndSize(buffer, size)
+        value = PyBytes_FromStringAndSize(buffer, size)
     else:
         value = PyUnicode_DecodeUTF8(buffer, size, 'strict')
     emitter.stream.write(value)