public static function checkForumsExistsDelete($ref_id, $user_id = 0)
 {
     global $ilUser;
     $node_data = self::getCachedNodeData($ref_id);
     include_once 'Modules/Forum/classes/class.ilForumModerators.php';
     foreach ($node_data as $data) {
         //check frm_properties if frm_noti is enabled
         $frm_noti = new ilForumNotification($data['ref_id']);
         $objFrmMods = new ilForumModerators($data['ref_id']);
         $moderator_ids = $objFrmMods->getCurrentModerators();
         if ($user_id != 0) {
             $frm_noti->setUserId($user_id);
         } else {
             $frm_noti->setUserId($ilUser->getId());
         }
         $frm_noti->setForumId($data['obj_id']);
         if (!in_array($frm_noti->getUserId(), $moderator_ids)) {
             $frm_noti->deleteAdminForce();
         }
     }
 }