I am very sorry, I just noticed another mistake.

It should be:

   A dotted lookup such as ``super(A, obj).x`` (where ``obj``
   is an instance of ``A`` or of a subclass of ``A``) searches
   ``type(obj).__mro__`` for such a base class ``B`` that follows
   ``A`` and whose :attr:`__dict__` contains the name ``"x"``;
   then ``B.__dict__['x'].__get__(obj, type(obj))`` is returned.
   If not a descriptor, ``B.__dict__['x']`` is returned unchanged.