code: def set_id(self, id='$'):
          
          return self.database.xgroup_setid(self.key, self.group, id)
docs: Set the last-read message id for the stream within the context of the
          parent :py:class:`ConsumerGroup`. By default this will be the special
          "$" identifier, meaning all messages are marked as having been read.
  
          :param id: id of last-read message (or "$").