code: def leave(self, _id):
          
          if SockJSRoomHandler._room.has_key(self._gcls() + _id):
              SockJSRoomHandler._room[self._gcls() + _id].remove(self)
              if len(SockJSRoomHandler._room[self._gcls() + _id]) == 0:
                  del SockJSRoomHandler._room[self._gcls() + _id]
docs: Leave a room