Pickle nested classes in Python

nested.py

import inspect
import pickle


def allow_picklable_inner_classes(cls):
    for name in dir(cls):
        inner = getattr(cls, name)

        if not name.startswith('_') and inspect.isclass(inner):
            new_name = '{}.{}'.format(cls.__name__, inner.__name__)
            inner.__name__ = new_name
            globals()[new_name] = inner

    return cls


@allow_picklable_inner_classes
class Outer(object):
    class Inner(object):
        pass


obj_1 = Outer.Inner()

obj_2 = pickle.loads(pickle.dumps(obj_1))

assert type(obj_1) == type(obj_2)