public static function listAllHtml()
 {
     self::preDispatch();
     $session = new Db_Session();
     $sessions = $session->getCollection();
     $preparedSessions = array_map(function ($x) {
         return $x['es_id'];
     }, $sessions);
     $invites = Invite::getAllInvites();
     if (!is_array($invites)) {
         $invites = array();
     }
     $tmpl = new \OCP\Template('documents', 'part.sessions', '');
     $tmpl->assign('invites', $invites);
     $tmpl->assign('sessions', $sessions);
     echo $tmpl->fetchPage();
 }