The broker example code can't executed successfully using master branch.

[zhonhel]

I cloned the master branch code, and cd to the code dir.
Then I executed the following code which copyed from https://amqtt.readthedocs.io/en/latest/references/broker.html and putted them into simple_broker.py

import logging
import asyncio
import os
from amqtt.broker import Broker


async def broker_coro():
    broker = Broker()
    await broker.start()


if __name__ == '__main__':
    formatter = "[%(asctime)s] :: %(levelname)s :: %(name)s :: %(message)s"
    logging.basicConfig(level=logging.INFO, format=formatter)
    asyncio.get_event_loop().run_until_complete(broker_coro())
    asyncio.get_event_loop().run_forever()

Then I got the following error:

(mqtt-server) wrp@ecs-2:~/amqtt$ python simple_broker.py 
Traceback (most recent call last):
  File "/home/wrp/amqtt/amqtt/broker.py", line 201, in _build_listeners_config
    listeners_config = broker_config["listeners"]
KeyError: 'listeners'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/wrp/amqtt/simple_broker.py", line 15, in <module>
    asyncio.get_event_loop().run_until_complete(broker_coro())
  File "/home/wrp/Python-3.9.13_install/lib/python3.9/asyncio/base_events.py", line 647, in run_until_complete
    return future.result()
  File "/home/wrp/amqtt/simple_broker.py", line 8, in broker_coro
    broker = Broker()
  File "/home/wrp/amqtt/amqtt/broker.py", line 173, in __init__
    self._build_listeners_config(self.config)
  File "/home/wrp/amqtt/amqtt/broker.py", line 208, in _build_listeners_config
    raise BrokerException("Listener config not found invalid: %s" % ke)
amqtt.broker.BrokerException: Listener config not found invalid: 'listeners'
(mqtt-server) wrp@ecs-2:~/amqtt$ 

[not-f-elsner]

Mh, I'm not sure if we should include a default listeners config in the broker, or if we should adapt the examples to provide such config

    "listeners":{
        "default":{
        "type": "tcp",
        "bind": "0.0.0.0:1883"
        } 
    },