How to use the tempora.timing.Stopwatch function in tempora

def wait_for_tables(cls, timeout=30):
        watch = tempora.timing.Stopwatch()
        while watch.split() < datetime.timedelta(seconds=timeout):
            try:
                cls.check_logs('#check')
                return
            except Exception:
                # short-circuit if the bot has stopped
                if cls.bot.poll() is not None:
                    return
                time.sleep(0.2)