code: def touch(self):
          
          marker_key = self.marker_key()
          self.redis_client.hset(marker_key, 'update_id', self.update_id)
          self.redis_client.hset(marker_key, 'date', datetime.datetime.now())
  
          if self.expire is not None:
              self.redis_client.expire(marker_key, self.expire)
docs: Mark this update as complete.
  
          We index the parameters `update_id` and `date`.