private static function isAction($type, $sub_type) {
    if ( ($type === 'content' && in_array($sub_type, array('create', 'create upload', 'update', 'update upload', 'upgrade', 'delete'))) ||
         ($type === 'library' && in_array($sub_type, array('create', 'update'))) ) {
      return TRUE; // Log actions
    }
    return FALSE;
  }