docs: function(name){
          var engines = this.doc.findall('./engine/[@name="' +name+'"]');
          for(var i=0; i < engines.length; i++){
              var children = this.doc.getroot().getchildren();
              var idx = children.indexOf(engines[i]);
              if(idx > -1){
                  children.splice(idx,1);
              }
          }
      }