I think python was a poor comparison here. The claim "python doesn't have algebraic data types" doesn't really make sense. Algebraic data types let something be

I think python was a poor comparison here. The claim "python doesn't have algebraic data types" doesn't really make sense. Algebraic data types let something be an X or a Y. In python, everything can be an X, or a Y, or a Z, or anything else. In the tree example, an ideomatic tree structure in python would just be a 3-tuple (left, right, value). There's no need to define anything. Don't get me wrong, I'm all for algebraic data types and think every statically typed language should have them, but it's nonsensical to talk about them in the context of a dynamically typed language. The author commented elsewhere on this page that the article was mostly a response to missing these features in golang - I think that would've been a much clearer comparison that showed what you were really missing.