def get_next_id(self):
        try:
            query = {'_id': 'last_id'}
            update = {'$inc': {'id': 1}}
            fn = self.db.internal.find_and_modify
            row = fn(query, update, upsert=True, new=True)
        except Exception as e:
            raise DatabaseException(e)
        return row['id']
def __init__(self, test, policer_index, is_ip6=False):
        self._test = test
        self._policer_index = policer_index
        self._is_ip6 = is_ip6