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:   bool hasClass(Element element, String classname) =>
        element.classes.contains(classname);
  
    setStyle(Element element, String stylename, String stylevalue) {
      element.style.setProperty(stylename, stylevalue);
    }
    removeStyle(Element element, String stylename) {
      element.style.removeProperty(stylename);
    }
    getStyle(Element element, String stylename) {
      return element.style.getPropertyValue(stylename);
    }
  
  
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,
  