anchor.diff:  
     Widget _buildImage(BuildContext context, String src) {
       List<String> parts = src.split('#');
  -    if (parts.length == 0) return new Container();
  +    if (parts.isEmpty) return new Container();
   
       String path = parts.first;
       double width;
  
positive.code: 
      Widget contents;
  
      if (subBlocks.length > 0) {
        List<Widget> subWidgets = <Widget>[];
        for (_Block subBlock in subBlocks) {
          subWidgets.add(subBlock.build(context));
  
negative.code:   bool get open => _open;
    set open(bool open) {
      _open = open;
      if (!open && subBlocks.isNotEmpty)
        subBlocks.last.isLast = true;
    }
  
  