public function updateSubscription($paymentId, $purpose)
    {
        $class = $this->resourceMetadata->resourceClass;
        /**
         * @var $object Transaction
         */
        $object = new $class();
        $object->id = $paymentId;
        $object->subscription = new Subscription();
        $object->subscription->purpose = $purpose;
        $res = $this->updateWithAction($paymentId, 'subscription', null, $object, $class);

        if ($res) {
            return true;
        }

        return false;
    }