def _parse_filter_arg(self, arg):
        statement = arg.rsplit('__', 1)
        if len(statement) == 1:
            return arg, None
        elif len(statement) == 2:
            return statement[0], statement[1]
        else:
            raise QueryException("Can't parse '{0}'".format(arg))
Check if the app is running on devserver or not.
dataset/ETHPy150Open datastax/python-driver/cassandra/cqlengine/query.py/AbstractQuerySet._parse_filter_arg--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/cloud-pubsub-samples-python/appengine-push/pubsub_utils.py/is_devserver