protected function curlExecute()
    {
        $response = curl_exec($this->getResource());

        $curlErrorNumber = $this->getErrorNumber();
        if ($curlErrorNumber) {
            /**
             * @var \OxidEsales\PayPalModule\Core\Exception\PayPalException $exception
             */
            $exception = oxNew(\OxidEsales\PayPalModule\Core\Exception\PayPalException::class, 'Curl error: ' . $curlErrorNumber);
            throw $exception;
        }

        return $response;
    }