Working with the network loop with Python

Now, we will use the previously coded functions to write a __main__ method that publishes many commands included in MQTT messages that the code controlling the drone will process. The following lines show the code for the __main__ method, that is, the main block of code. The code file for the sample is included in the mqtt_essentials_gaston_hillar_03 folder, in the mqtt_essentials_example03_03.py file:

if __name__ == "__main__":
    client = mqtt.Client(protocol=mqtt.MQTTv311)
    client.on_connect = on_connect
    client.on_subscribe = on_subscribe
    client.on_message = on_message
    client.tls_set(ca_certs = ca_certificate,
        certfile=client_certificate,
        keyfile=client_key)
    client.connect(host=mqtt_server_host,
        port=mqtt_server_port,
        keepalive=mqtt_keepalive)
    publish_command(client, CMD_TAKE_OFF)
    publish_command(client, CMD_MOVE_UP)
    publish_command(client, CMD_ROTATE_LEFT, KEY_DEGREES, 90)
    publish_command...