def reverse(self):
        clone = self._clone()
        clone.query.standard_ordering = not clone.query.standard_ordering
        return clone
Check that a thread running a select_for_update that
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/django/db/models/query.py/QuerySet.reverse--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/tests/modeltests/select_for_update/tests.py/SelectForUpdateTests.test_block