public function getContentH1s()
 {
     if (!isset($this->contentH1s)) {
         $this->contentH1s = array();
         $pages = $this->getPages();
         foreach ($pages as $page) {
             $pageContentH1Maps = Collection::instance('PageContentH1Map')->setPageFilter($page->getID())->getPageContentH1Maps();
             if (!$pageContentH1Maps) {
                 continue;
             }
             foreach ($pageContentH1Maps as $pageContentH1Map) {
                 $this->contentH1s[] = $pageContentH1Map->getContentH1();
             }
         }
     }
     return $this->contentH1s;
 }