`mypy` compatibility monkey patch

Currently, there is no monkey patching being done to add MyPy compatibility.

See [django-stubs-ext](https://github.com/typeddjango/django-stubs/blob/8b1e20c35a2917f6ea220b4c89201d7e2e3c8692/django_stubs_ext/django_stubs_ext/patch.py#L77) for how this can be done.