Describe the bug

Unexpected error for utilization of custom message classes in Rhino.

Runtime error (ArgumentTypeException): expected type, got classobj

Expected behavior

This is a result of the Message class inheriting from UserDict which is an OldStyle class and does not operate properly in the rhino environment (python 2.7)

class Message(UserDict):

Desktop (please complete the following information):

• OS: [e.g. Windows]
• Python version [2.7]

Problem:

In the file mqtt_paho.py
when creating a client

self.client = mqtt.Client()

the new mqtt 2.0 version will give a error.

Fix:

from paho.mqtt.enums import CallbackAPIVersion
self.client = mqtt.Client(callback_api_version = CallbackAPIVersion.VERSION1)

Feature Request

It would be nice if - instead of subclassing Publisher and Subscriber classes to override message_received() and message_published() methods - the user could pass the custom method as a callback argument to these classes.