docs: private void checkForDuplicateAttributes(ParentSoyNode<StandaloneNode> parentNode) {
      DuplicateAttributesVisitor visitor = new DuplicateAttributesVisitor();
      List<StandaloneNode> children = parentNode.getChildren();
      if (parentNode instanceof HtmlTagNode) {
        // the first child is the tag name, which isn't interesting, so skip it
        children = children.subList(1, children.size());
      }
      for (SoyNode child : children) {
        visitor.exec(child);
      }
    }