QMP_SHELL on_recv return none on exception

gistfile1.txt

DEBUG:asyncio:Using selector: EpollSelector
DEBUG:aqmp.qmp_protocol:Connecting ...
DEBUG:asyncio:Get address info localhost:1234, type=<SocketKind.SOCK_STREAM: 1>
DEBUG:asyncio:Getting address info localhost:1234, type=<SocketKind.SOCK_STREAM: 1> took 1.495ms: [(<AddressFamily.AF_INET: 2>, <SocketKind.SOCK_STREAM: 1>, 6, '', ('127.0.0.1', 1234))]
DEBUG:asyncio:<asyncio.TransportSocket fd=9, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=6, laddr=('127.0.0.1', 37744), raddr=('127.0.0.1', 1234)> connected to localhost:1234: (<_SelectorSocketTransport fd=9 read=polling write=<idle, bufsize=0>>, <asyncio.streams.StreamReaderProtocol object at 0x7fe7b3aaa910>)
DEBUG:aqmp.qmp_protocol:Connected
DEBUG:aqmp.qmp_protocol:Awaiting greeting ...
DEBUG:aqmp.qmp_protocol:<-- {
  "QMP": {
    "version": {
      "qemu": {
        "micro": 50,
        "minor": 2,
        "major": 5
      },
      "package": "v5.2.0-1732-g1684f1f499-dirty"
    },
    "capabilities": [
      "oob"
    ]
  }
}
DEBUG:aqmp.qmp_protocol:Negotiating capabilities ...
DEBUG:aqmp.qmp_protocol:Execute(__aqmp#00000): 'qmp_capabilities'
DEBUG:aqmp.qmp_protocol:--> {
  "execute": "qmp_capabilities",
  "arguments": {
    "enable": [
      "oob"
    ]
  },
  "id": "__aqmp#00000"
}
DEBUG:aqmp.qmp_protocol:<-- {
  "return": {},
  "id": "__aqmp#00000"
}
DEBUG:aqmp.qmp_protocol:<-- {
  "timestamp": {
    "seconds": 1622740631,
    "microseconds": 387568
  },
  "event": "SHUTDOWN",
  "data": {
    "guest": false,
    "reason": "host-ui"
  }
}
DEBUG:asyncio:<_SelectorSocketTransport fd=9 read=polling write=<idle, bufsize=0>> received EOF
DEBUG:aqmp.qmp_protocol:EOF
DEBUG:root:Received EOF
DEBUG:aqmp.qmp_protocol:<-- None
ERROR:aqmp.qmp_protocol:Task.Reader: failure:
  | Traceback (most recent call last):
  |   File "/home/niteesh/development/qmp_shell_prototype/aqmp/protocol.py", line 539, in _bh_loop_forever
  |     await async_fn()
  |   File "/home/niteesh/development/qmp_shell_prototype/aqmp/protocol.py", line 576, in _bh_recv_message
  |     await self._on_message(msg)
  |   File "/home/niteesh/development/qmp_shell_prototype/aqmp/qmp_protocol.py", line 190, in _on_message
  |     if 'event' in msg:
  | TypeError: argument of type 'NoneType' is not iterable

DEBUG:aqmp.qmp_protocol:Task.Reader: scheduling disconnect.
DEBUG:aqmp.qmp_protocol:Task.Reader: exiting.
DEBUG:aqmp.qmp_protocol:cancelling task <Task pending name='Task-4' coro=<AsyncProtocol._bh_loop_forever() running at /home/niteesh/development/qmp_shell_prototype/aqmp/protocol.py:539> wait_for=<Future pending cb=[<TaskWakeupMethWrapper object at 0x7fe7b39f3b80>()] created at /usr/lib/python3.8/asyncio/base_events.py:418> cb=[gather.<locals>._done_callback() at /usr/lib/python3.8/asyncio/tasks.py:751] created at /usr/lib/python3.8/asyncio/tasks.py:382>
DEBUG:aqmp.qmp_protocol:Awaiting all tasks to finish ...
DEBUG:aqmp.qmp_protocol:Task.Writer: cancelled: CancelledError.
DEBUG:aqmp.qmp_protocol:Task.Writer: exiting.
DEBUG:aqmp.qmp_protocol:Writer is open; draining
DEBUG:aqmp.qmp_protocol:Closing writer
DEBUG:aqmp.qmp_protocol:Awaiting writer to fully close
DEBUG:aqmp.qmp_protocol:Fully closed.
DEBUG:aqmp.qmp_protocol:Disconnected.
DEBUG:aqmp.qmp_protocol:Disconnected.
DEBUG:root:argument of type 'NoneType' is not iterable