subscribe.py

import paho.mqtt.client as paho
broker="192.168.xx.xxx" #IP of your Raspberry Pi

def on_message(client, userdata, message):
     print("received message =",str(message.payload.decode("utf-8")))

client= paho.Client("client-001")
client.on_message=on_message

print("connecting to broker ",broker)
client.connect(broker)
print("subscribing ")
client.subscribe("sensor_data")
client.loop_forever()