Backed out Reify() signature change.

python/map.h

diff --git a/python/map.h b/python/map.h
index 46ae75d..9f6f969 100644
--- a/python/map.h
+++ b/python/map.h
@@ -47,6 +47,7 @@
                                                 PyObject* arena);
 
 // Reifies a map stub to point to the concrete data in `map`.
+// If `map` is NULL, an appropriate empty map will be constructed.
 void PyUpb_MapContainer_Reify(PyObject* self, upb_map* map);
 
 // Reifies this map object if it is not already reified.

python/repeated.c

diff --git a/python/repeated.c b/python/repeated.c
index 0b25f4c..4794fc1 100644
--- a/python/repeated.c
+++ b/python/repeated.c
@@ -106,7 +106,7 @@
   return PyUpb_RepeatedContainer_IsStub(self) ? NULL : self->ptr.arr;
 }
 
-upb_array* PyUpb_RepeatedContainer_Reify(PyObject* _self, upb_array* arr) {
+void PyUpb_RepeatedContainer_Reify(PyObject* _self, upb_array* arr) {
   PyUpb_RepeatedContainer* self = (PyUpb_RepeatedContainer*)_self;
   assert(PyUpb_RepeatedContainer_IsStub(self));
   if (!arr) {
@@ -119,7 +119,6 @@
   self->ptr.arr = arr;  // Overwrites self->ptr.parent.
   self->field &= ~(uintptr_t)1;
   assert(!PyUpb_RepeatedContainer_IsStub(self));
-  return arr;
 }
 
 upb_array* PyUpb_RepeatedContainer_EnsureReified(PyObject* _self) {

python/repeated.h

diff --git a/python/repeated.h b/python/repeated.h
index ec2ac16..de81b2b 100644
--- a/python/repeated.h
+++ b/python/repeated.h
@@ -48,7 +48,8 @@
                                                      PyObject* arena);
 
 // Reifies a repeated field stub to point to the concrete data in `arr`.
-upb_array* PyUpb_RepeatedContainer_Reify(PyObject* self, upb_array* arr);
+// If `arr` is NULL, an appropriate empty array will be constructed.
+void PyUpb_RepeatedContainer_Reify(PyObject* self, upb_array* arr);
 
 // Reifies this repeated object if it is not already reified.
 upb_array* PyUpb_RepeatedContainer_EnsureReified(PyObject* self);