protected function _assignComparisonListFlag()
    {
        // #657 add a flag if article is on comparisonlist

        $aItems = \OxidEsales\Eshop\Core\Registry::getSession()->getVariable('aFiltcompproducts');
        if (isset($aItems[$this->getId()])) {
            $this->_blIsOnComparisonList = true;
        }
    }