anchor.diff:      _elements = elements;
     }
   
  +  // TODO: we do not need 'type' (or replace it by isXml)
     DomNode.fromString(String str,
         {String type: 'text/xml',
         NodeValidator validator,
  
positive.code:       throw new ArgumentError(new ParserError(result).toString());
      }
  
      DomParser domParser = new DomParser();
      Document doc = domParser.parseFromString(str, type);
      _elements = [doc.documentElement];
    }
  
    List<Element> get elements => this._elements;
  
negative.code: part of domnode;
  // TODO: remove validator y sanitizer from constructors
  // TODO: simplify the '$' function
  // TODO: add a 'query' function
  
  /**
   * This class represents one or more DOM elements.
  