protected function is_question_file($path)
 {
     $name = basename($path);
     $ext = pathinfo($path, PATHINFO_EXTENSION);
     if (empty($ext) || $ext != 'xml' || self::IMS_MANIFEST_NAME == $name) {
         return false;
     }
     $reader = new ImsQtiReader();
     $reader->load($path);
     return count($reader->query('/def:assessmentItem')) > 0;
 }