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 wait_time_gen():
        count = 0
        while True:
            rand = random.randrange(round(interval.total_seconds()))
            tmp = round(start + interval.total_seconds() * count + rand - loop.time())
            yield tmp
            count += 1