public function __construct($data, $data_is_url = false)
 {
     parent::__construct(AtomNS::CATEGORY_ELEMENT, $data, $data_is_url);
 }
 public function __construct($data, $data_is_url = false)
 {
     parent::__construct(AtomNS::GENERATOR_ELEMENT, $data, $data_is_url);
 }