@python_2_unicode_compatible
    def __str__(self):
        return "%sZ" % (self._dt_obj.isoformat(), )
test db query with '$in','$nin' operators
dataset/ETHPy150Open lugensa/scorched/scorched/dates.py/solr_date.__str__--crossover with--dataset/ETHPy150Open ipython/ipython-py3k/IPython/parallel/tests/test_client.py/TestClient.test_db_query_in