new_contents: import paho.mqtt.client as mqtt
  #
  # Original code: https://tutorials-raspberrypi.com/raspberry-pi-mqtt-broker-client-wireless-communication/
  #
  
  MQTT_SERVER = "localhost"
  MQTT_PATH = "test_channel"
   
  # The callback for when the client receives a CONNACK response from the server.
  def on_connect(client, userdata, flags, rc):
      print("Connected with result code "+str(rc))
   
      # Subscribing in on_connect() means that if we lose the connection and
      # reconnect then subscriptions will be renewed.
      client.subscribe(MQTT_PATH)
   
  # The callback for when a PUBLISH message is received from the server.
  def on_message(client, userdata, msg):
      print(msg.topic+" "+str(msg.payload))
      # more callbacks, etc
   
  client = mqtt.Client()
  client.on_connect = on_connect
  client.on_message = on_message
   
  client.connect(MQTT_SERVER, 1883, 60)
   
  # Blocking call that processes network traffic, dispatches callbacks and
  # handles reconnecting.
  # Other loop*() functions are available that give a threaded interface and a
  # manual interface.
  client.loop_forever()
  
subject: Create mqtt_subscriber.py