<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def expire_hit(self, hit_id):
 """Expire a HIT, which will change its status to "Reviewable", allowing it to be deleted. """

        try:
            self.mturk.update_expiration_for_hit(HITId=hit_id, ExpireAt=0)
        except Exception as ex:
            raise MTurkServiceException(
                "Failed to expire HIT {}: {}".format(hit_id, str(ex))
            )
        return True