static function get_form_to_cleanrif_transformer()
 {
     if (is_null(self::$form_to_cleanrif_transformer)) {
         $cleanEmtyTags = new DomDocument();
         $cleanEmtyTags->load(REGISTRY_APP_PATH . 'registry_object/transforms/clean_empty_tags.xsl');
         $cleanEmtyTagsproc = new XSLTProcessor();
         $cleanEmtyTagsproc->importStyleSheet($cleanEmtyTags);
         self::$form_to_cleanrif_transformer = $cleanEmtyTagsproc;
     }
     return self::$form_to_cleanrif_transformer;
 }