code: def remove_send_message(self, connection):
          
          if connection in self._send_message:
              del self._send_message[connection]
              LOGGER.debug("Removed send_message function "
                           "for connection %s", connection)
          else:
              LOGGER.warning("Attempted to remove send_message "
                             "function for connection %s, but no "
                             "send_message function was registered",
                             connection)
docs: Removes a send_message function previously registered
          with the Dispatcher.
  
          Args:
              connection (str): A locally unique identifier provided
                  by the receiver of messages.