def achievement_for_id(self, tracked_id, achievement):
        """ Retrieves the current ``Achievement`` for the given ``tracked_id``. If the given
        ``tracked_id`` does not exist yet, it should be created. Also, if the given ``tracked_id``
        hasn't tracked the given ``Achievement`` yet, a new instance of the ``Achievement`` should
        be created for the given ``tracked_id``"""
        if tracked_id not in self._tracked:
            self._tracked[tracked_id] = {}
        if achievement.__name__ not in self._tracked[tracked_id]:
            self._tracked[tracked_id][achievement.__name__] = achievement()
        return self._tracked[tracked_id][achievement.__name__]
dataset/ETHPy150Open PacketPerception/pychievements/pychievements/backends.py/AchievementBackend.achievement_for_id/original