anchor.diff:    Element remove(Element el) {
       return el..remove();
     }
  -  insertBefore(Node el, node) {
  +  void insertBefore(Node el, node) {
       el.parentNode.insertBefore(node, el);
     }
     void insertAllBefore(Node el, Iterable<Node> nodes) {
  
positive.code:   }
  
    @override
    final attrToPropMap = const {
      'innerHtml': 'innerHtml',
      'readonly': 'readOnly',
      'tabindex': 'tabIndex',
    };
  
    query(String selector) => document.querySelector(selector);
  
    Element querySelector(el, String selector) => el.querySelector(selector);
  
  
negative.code:     if (doc == null) doc = document;
      return doc.createElement(tagName);
    }
    Text createTextNode(String text, [HtmlDocument doc = null]) {
      return new Text(text);
    }
    createScriptTag(String attrName, String attrValue,
  