public function Link($action = null)
 {
     if ($this->URLSegment == get_class($this) && ($segment = self::config()->url_segment)) {
         $this->data()->URLSegment = $segment;
     }
     return parent::Link($action);
 }
 function Link($action = null)
 {
     if ($this->isInDB()) {
         return parent::Link($action);
     }
     return Controller::join_links(self::$url_segment, $action);
 }