Unable to query a string key that contains only numbers

[thugdoubt]

Given the following data:

endpoint_call_types = {u'1111': u'missed', u'barf': u'missed'}

A query using filter(endpoint_call_types__at_1111='missed') fails, despite the key being a string, because django-pgjson is attempting to perform magic. The query filter(endpoint_call_types__at_barf='missed') succeeds, natch.

List index queries should use a different operator than key operations since they are, in fact, two separate operations.