docs: def pub(topic_name, json_msg, repeat_rate=None, host=jps.env.get_master_host(), pub_port=jps.DEFAULT_PUB_PORT):
      '''publishes the data to the topic
  
      :param topic_name: name of the topic
      :param json_msg: data to be published
      :param repeat_rate: if None, publishes once. if not None, it is used as [Hz].
      '''
      pub = jps.Publisher(topic_name, host=host, pub_port=pub_port)
      time.sleep(0.1)
      if repeat_rate is None:
          pub.publish(json_msg)
      else:
          try:
              while True:
                  pub.publish(json_msg)
                  time.sleep(1.0 / repeat_rate)
          except KeyboardInterrupt:
              pass