protected function validateOrderCart()
    {
        $field = 'order_id';
        $value = $this->getSubmitted($field);

        if (empty($value)) {
            return null;
        }

        $label = $this->translation->text('Order');

        if (!is_numeric($value)) {
            $this->setErrorNumeric($field, $label);
            return false;
        }

        $order = $this->order->get($value);

        if (empty($order['order_id'])) {
            $this->setErrorUnavailable($field, $label);
            return false;
        }

        return true;
    }