function onReceive(responseCode as Lang.Number, data as Lang.Dictionary or Lang.String or Null) as Void {
        System.println("onReceive: response code: " + responseCode + ", data: " + data);
        if (responseCode == 200) {
            var dict = data as Dictionary;
            var payload = dict["payload"] as Lang.Array<Lang.Dictionary>;
            var val = payload[0]["val"] as Lang.Float;
            Background.exit(val);
        }
        Background.exit(null);
    }

    public function onTemporalEvent() as Void {
        Communications.makeWebRequest(
            "https://api.existenz.ch/apiv1/hydro/latest",
            {
                "locations" => "2030",
                "version" => "1.042",
                "parameters" => "temperature"
            },
            {
                :method => Communications.HTTP_REQUEST_METHOD_GET,
                :responseType  => Communications.HTTP_RESPONSE_CONTENT_TYPE_JSON
            },
            method(:onReceive)
        );
    }