Currently, if I want to have weakref.finalize call an object's cleanup method, I have to do something like: class foo: _finalizer = None def __init__(self): self._finalizer = weakref.finalize(self, foo._cleanup, weakref.WeakMethod(self.cleanup)) def __del__(self): self.cleanup() @classmethod def _cleanup(cls, func): func()() def cleanup(self): if self._finalizer is not None: self._finalizer.detach() print('cleaning up') It wouldn't be difficult to have weakref.finalize automatically handle the conversion to WeakMethod and automatically attempt to dereference then call the function passed in.