Suor/django-cacheops — pull request #99 by sheats (2014-07-14 02:53:13+00:00)
Title: A PointField with a None value raises a "ValueError: Cannot use object w...

...ith type NoneType for a geometry lookup parameter" error when trying to invalidate the object.

This was my quick and dirty fix... probably needs someone that understands the code better to tweak.