Returns a list of handlers for the specific event.

        :param ev: The event to handle.
        :param state: The current state. ("dispatcher")
                      If None is given, returns all handlers for the event.
                      Otherwise, returns only handlers that are interested
                      in the specified state.
                      The default is None.

def get_handlers(self, ev, state=None):
        """Returns a list of handlers for the specific event.

        :param ev: The event to handle.
        :param state: The current state. ("dispatcher")
                      If None is given, returns all handlers for the event.
                      Otherwise, returns only handlers that are interested
                      in the specified state.
                      The default is None.
        """
        ev_cls = ev.__class__
        handlers = self.event_handlers.get(ev_cls, [])
        if state is None:
            return handlers

        def test(h):
            if not hasattr(h, 'callers') or ev_cls not in h.callers:
                # dynamically registered handlers does not have
                # h.callers element for the event.
                return True
            states = h.callers[ev_cls].dispatchers
            if not states:
                # empty states means all states
                return True
            return state in states

        return filter(test, handlers)