def current_batch(self):
        """Return the batch id for the tag.

        :return: :class: `int` current batch id
        """
        current_batch = memcache.get(self.group_key)

        if not current_batch:
            memcache.add(self.group_key, 1)
            current_batch = 1

        return current_batch
Return the batch id for the tag.

        :return: :class: `int` current batch id