public function getRDFaValidityPeriod($configVariableName)
    {
        if ($configVariableName) {
            $validity = [];
            $days = \OxidEsales\Eshop\Core\Registry::getConfig()->getConfigParam($configVariableName);
            $from = \OxidEsales\Eshop\Core\Registry::getUtilsDate()->getTime();

            $through = $from + ($days * 24 * 60 * 60);
            $validity["from"] = date('Y-m-d\TH:i:s', $from) . "Z";
            $validity["through"] = date('Y-m-d\TH:i:s', $through) . "Z";

            return $validity;
        }

        return false;
    }