How to use the nameko.events.event_handler function in nameko

            @event_handler('service', 'event1')
            def handle_event1(self, event_data):
                self.upstream_rpc.method()

            @event_handler('service', 'event')
            def handle(self, event_data):
                time.sleep(9)  # >2x heartbeat
                tracker(event_data)

            @event_handler("service", "event")
            @rpc
            def echo(self, arg):
                return arg  # pragma: no cover

    @event_handler('foo-service', 'spam')
    def handle_spam(self, evt_data):
        ham = self.foo_service.spam(evt_data)
        handle_spam_called(ham)

    @event_handler("orders_service", "order_created")
    @statsd.timer('request_reservation')
    def place_order(self, payload):
        print("service {} received: {} ... placing order to exchange".format(
            self.name, payload))

        # place order in stock exchange
        exchange_resp = self.__place_order_exchange(payload)
        # event: emit order placed event
        self.__create_event("order_placed", payload)

        return json.dumps({'exchange_response': exchange_resp})

    @event_handler("eventgen_controller", "{}_setup".format(eventgen_name), handler_type=BROADCAST,
                   reliable_delivery=False)
    def event_handler_setup(self, payload):
        return self.setup(data=payload)

    @event_handler("eventgen_controller", "all_index", handler_type=BROADCAST, reliable_delivery=False)
    def event_handler_all_index(self, payload):
        return self.index()

    @event_handler("eventgen_controller", "{}_set_volume".format(eventgen_name), handler_type=BROADCAST,
                   reliable_delivery=False)
    def event_handler_set_volume(self, payload):
        if payload['perDayVolume']:
            return self.set_volume(payload['perDayVolume'])

    @event_handler("market_service", "order_placed")
    @statsd.timer('place_order')
    def handle_place_order(self, payload):
        print("[{}] {} received order_placed event ... updating order to placed".format(
            payload, self.name))

    @event_handler("eventgen_server", "server_volume", handler_type=BROADCAST, reliable_delivery=False)
    def event_handler_get_volume(self, payload):
        return self.receive_volume(payload)