code: def remove_port_callback(self, port, cb):
          
          logger.debug('Removing callback on port [%d] to [%s]', port, cb)
          for port_callback in self.cb:
              if port_callback.port == port and port_callback.callback == cb:
                  self.cb.remove(port_callback)
docs: Remove a callback for data that comes on a specific port