public function setUrlToCall($urlToCall)
    {
        if (false === filter_var($urlToCall, FILTER_VALIDATE_URL)) {
            /**
             * @var \OxidEsales\PayPalModule\Core\Exception\PayPalException $exception
             */
            $exception = oxNew(\OxidEsales\PayPalModule\Core\Exception\PayPalException::class, 'URL to call is not valid.');
            throw $exception;
        }
        $this->urlToCall = $urlToCall;
    }