code: def message(self, executor_id, slave_id, message):
          
          logging.info('Sends message `{}` to executor `{}` on slave `{}`'.format(
                       message, executor_id, slave_id))
          return self.driver.sendFrameworkMessage(encode(executor_id),
                                                  encode(slave_id),
                                                  message)
docs: Sends a message from the framework to one of its executors.
  
          These messages are best effort; do not expect a framework message to be
          retransmitted in any reliable fashion.