protected function validateResponse($response)
    {
        if (isset($response->code) && isset($response->message)) {
            if ($response->code == $this->validResponseCode &&
                $response->message == $this->validResponseMessage
            ) {
                // serial keys are valid
                $valid = true;
            } else {
                // serial keys are not valid
                $this->setErrorMessage(\OxidEsales\Eshop\Core\Registry::getLang()->translateString('OLC_ERROR_SERIAL_NOT_VALID'));
                $valid = false;
            }
        } else {
            // validation result is unknown
            throw new \OxidEsales\Eshop\Core\Exception\StandardException('OLC_ERROR_RESPONSE_NOT_VALID');
        }

        return $valid;
    }