code: def set_subject(self,subject):
          
          m=Message(to_jid=self.room_jid.bare(),stanza_type="groupchat",subject=subject)
          self.manager.stream.send(m)
docs: Send a subject change request to the room.
  
          :Parameters:
              - `subject`: the new subject.
          :Types:
              - `subject`: `unicode`