- In Python code, __objclass__ should be the defining class, not the module.

Indeed. My idea would be to add an accessor __parent__ returning the m_parent field (whatever it is) and then implement __objclass__ as something like: @property def __objclass__(self): parent = getattr(self, "__parent__", None) if isinstance(parent, type): return parent else: raise AttributeError In PEP 575, I don't plan to add a Python attribute specifically for getting the defining module: I'll leave that to PEP 573.