According to the doc ( https://docs.python.org/3/library/pickle.html#object.__getstate__ ), an object may not have a __getstate__ method.

During pickling and unpickling, python first finds __getstate__ and __setstate__, which may invoke a customed __getattr__. I think this is unnecessary if python just provides a default implementation for __getstate__ / __setstate__ . An additional benefit of this is that __setstate__ and __getstate__ becomes available for every object and it is possible to do something like ``getstate(obj)``.

For people who customize __getattr__, I think no one intends to deal with ``obj.__getattr__（“__getstate__”）``, so it makes sense not to invoke ``__getattr__`` during pickling and unpickling.

This is virtually a duplicate of isssue26579.