anchor.diff:        _listIndents.removeLast();
   
       if (_isBlockTag(element.tag)) {
  -      if (_currentBlock.stack.length > 0) {
  +      if (_currentBlock.stack.isNotEmpty) {
           _MarkdownNodeList stackList = _currentBlock.stack.first;
           _currentBlock.stack = stackList.list;
           _currentBlock.open = false;
  
positive.code: 
      Widget contents;
  
      if (subBlocks.length > 0) {
        List<Widget> subWidgets = <Widget>[];
        for (_Block subBlock in subBlocks) {
          subWidgets.add(subBlock.build(context));
  
negative.code: 
    Widget _buildImage(BuildContext context, String src) {
      List<String> parts = src.split('#');
      if (parts.isEmpty) return new Container();
  
      String path = parts.first;
      double width;
  