def __call__(event, bubbled=False, rule_filter=None):
    """Execute all rules applicable in the current context

        event is the triggering event. bubbled should be True if the rules
        are being executed as part of a bubbling up of events (i.e. this
        is a parent of the context where the event was triggered). filter,
        if given, is a callable that will be passed each rule in turn and
        can vote on whether it should be executed by returning True or
        False. It should take the arguments (context, rule, event).
        """
