cython: Fix 2 warnings with `-Wbad-function-cast`
diff --git a/cython/plist.pyx b/cython/plist.pyx
index bfecf85..38415f9 100644
--- a/cython/plist.pyx
+++ b/cython/plist.pyx
@@ -189,7 +189,8 @@
         return self.get_value()
 
     def __float__(self):
-        return float(self.get_value())
+        v = self.get_value()
+        return float(v)
 
     def __richcmp__(self, other, op):
         cdef int i = self.get_value()
@@ -281,7 +282,8 @@
         return self.get_value()
 
     def __float__(self):
-        return float(self.get_value())
+        v = self.get_value()
+        return float(v)
 
     def __richcmp__(self, other, op):
         cdef int i = self.get_value()