public function getIPNRequestVerifier()
    {
        if (is_null($this->ipnRequestVerifier)) {
            $ipnRequestVerifier = oxNew(\OxidEsales\PayPalModule\Model\IPNRequestVerifier::class);
            $this->setIPNRequestVerifier($ipnRequestVerifier);
        }

        return $this->ipnRequestVerifier;
    }