(lamada x:
      (x+x)
      /x)(n)

Will work, though in Python I usually just create an outside function and pass that in.

But yes, not everything in Python is nice for working with fp code. Using tuples, coming from Clojure, is painful. Things like returning exceptions for `StopIteration`is annoying. Mutability of lists outside of a lexical scope without using deepcopy. Though functools and itertools makes it more bearable.

But I also don't think types is the answer. I think something like Racket's contracts or Clojure's spec is closer to what I'd prefer. Gradual typing is nice though.