anchor.diff:        final html.Element r = ref;
   
         if (!identical(attrs, other.attrs)) {
  -        _updateMap(attrs, other.attrs, r.attributes);
  +        updateAttrs(attrs, other.attrs, r.attributes);
         }
   
         if (!identical(style, other.style)) {
  -        _updateStyle(style, other.style, r.style);
  +        updateStyle(style, other.style, r.style);
         }
   
         if (!identical(classes, other.classes)) {
  -        _updateSet(classes, other.classes, r.classes);
  +        updateClasses(classes, other.classes, r.classes);
         }
   
         if ((flags & componentFlag) != 0) {
  
positive.code: }
  
  /// Find changes between Lists [a] and [b] and apply this changes to Set [n].
  void _updateSet(List a, List b, Set n) {
    if (a != null && a.length > 0) {
      if (b == null || b.length == 0) {
        n.removeAll(a);
  
negative.code: }
  
  /// Find changes between maps [a] and [b] and apply this changes to map [n].
  void updateAttrs(Map a, Map b, Map n) {
    if (a != null && a.length > 0) {
      if (b == null || b.length == 0) {
        // all keys removed
  