...

python/builtins.py

@@ -183,8 +183,8 @@ class property:
     def __init__(self, fget, fset=None):
         self.fget = fget
         self.fset = fset
-        if '__doc__' in fget.__dict__:
-            self.__doc__ = fget.__dict__['__doc__']
+        if hasattr(fget, '__doc__'):
+            self.__doc__ = fget.__doc__
 
     def __get__(self, obj):
         return self.fget(obj)