public function parse($value, $sub)
    {
        $page = Nav::findOne($value);
        
        // verify if the page is of type content

        if ($page) {
            if ($page->activeLanguageItem->nav_item_type !== NavItem::TYPE_PAGE) {
                return null;
            }
            
            if (empty($sub)) {
                return $page->activeLanguageItem->getContent();
            } else {
                return $page->activeLanguageItem->type->renderPlaceholder($sub);
            }
        }
        
        return null;
    }