I vastly prefer the second one, as I would expect to see it written something like this:

  tree
    .map(node => node.find(SOME_XPATH))
    .filter(Boolean)
    .map(node => node.get("value"))

I don't use Python on a daily basis, but I find that infinitely more readable than the comprehension version (plus, it's a syntax used in several major languages)

In fairness, the Python also should be broken up. It should be:

    [
      found_node.get("value") 
      for node in tree 
      if (found_node := node.find(SOME_XPATH)) is not None
    ]

I think I also prefer Ruby/Javascript style comprehensions, but it's worth comparing well formatted code.

What is "node => ", is that valid Python? I'm new to the language and have never seen the => syntax before. The docs for 'map' don't show it either.

It's not Python, the second is actually a counterexample in JavaScript, where `node =>` is similar to Python's `lambda node:`