error.py

ERROR    Unhandled exception in HueFrontend (urn:uuid:dd0e9db2-53d7-4a49-80a8-e633dc44f796):
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/pykka/actor.py", line 201, in _actor_loop
    response = self._handle_receive(message)
  File "/usr/local/lib/python2.7/site-packages/pykka/actor.py", line 295, in _handle_receive
    return callee(*message['args'], **message['kwargs'])
TypeError: on_event() got an unexpected keyword argument ‘old_state’

frontend.py

import pykka
import logging

from mopidy import core

logger = logging.getLogger(__name__)

class HueFrontend(pykka.ThreadingActor, core.CoreListener):
    def __init__(self, config, core):
        super(HueFrontend, self).__init__()
        self.core = core

    def on_event(self, event):
        print event