This is a generic mixin that can add action handlers to any other class

handler_test.py

class HandlerMixin(object):
    action_handlers = {}
 
    def add_handler_action(self,action):
        if action not in self.action_handlers.keys():
            self.action_handlers[action] = []
 
    def register_handler(self, action, function):
        self.add_handler_action(action)
        if function not in self.action_handlers[action]:
            self.action_handlers[action].append(function)
 
    def call_handlers(self, action):
        for each_func in self.action_handlers[action]:
            each_func.__call__()
 
if __name__ == "__main__":
  def test_function():
    print "inside test function"
  mything = HandlerMixin()
  # This will only register the handler once per action even if you call it many times
  mything.register_handler("on_wake", test_function)
  mything.register_handler("on_wake", test_function)
  mything.register_handler("on_wake", test_function)
  mything.call_handlers("on_wake")