public function set($url) {
        $client = $this->module->getAmazonV1Client();

        // possible array values: ALL, ORDER_REFERENCE, PAYMENT_AUTHORIZE, PAYMENT_CAPTURE,
        // PAYMENT_REFUND, BILLING_AGREEMENT, CHARGEBACK_DETAILED
        $notificationConfiguration[$url] = ['ALL'];
        $requestParameters['notification_configuration_list'] = $notificationConfiguration;

        $response = $client->setMerchantNotificationConfiguration($requestParameters);

        return $response->toArray();
    }