def get(self, key, default=None, version=None):
        raise NotImplementedError
ensures we get a queryset descriptor back
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/core/cache/backends/base.py/BaseCache.get--crossover with--dataset/ETHPy150Open datastax/python-driver/tests/integration/cqlengine/test_ttl.py/TTLModelTests.test_queryset_is_returned_on_class