Unsupported set_exception() in python >=3.8

[dargor0]

Using amqtt version 0.10.0 , with python 3.8.10 , on unexpected disconnections, this message is reported:

Task exception was never retrieved
future: <Task finished name='Task-622' coro=<MQTTClient.handle_connection_close() done, defined at /usr/local/lib/python3.8/dist-packages/amqtt/client.py:504> exception=RuntimeError('Task does not support set_exception operation')>
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/dist-packages/amqtt/client.py", line 535, in handle_connection_close
    cancel_tasks()
  File "/usr/local/lib/python3.8/dist-packages/amqtt/client.py", line 510, in cancel_tasks
    task.set_exception(ClientException("Connection lost"))
RuntimeError: Task does not support set_exception operation

It seems Task objects don't inherit set_exception() (as explained here). A quick workaround is replace them with task.cancel().