Regarding the use of 'sets' instead of 'lists' to store nodes.

[DTRademaker]

I discussed with @cbaakman today, and he believes that using lists should suffice, and there may not be a need for sets. He had initially considered using sets as a precautionary measure to avoid accidental duplication of nodes. However, he now thinks that such occurrences are unlikely.

[github-actions[bot]]

This issue is stale because it has been open for 30 days with no activity.