I strongly dislike python, I often wonder if it would have been as popular if Guido didn't work at Google early on.

But you only ever need to unwrap one sum(). And with sequence comprehensions, what you get instead is sum(... for ... if ... for ... if ...) - I don't think that's improved by rewriting it as (...).sum().

I bet a Clojure-style ‘threading’ arrow function can be easily done in Python.

  arrow(my_list [map args] [filter args] [filter args] [map args] [sum])

For cases when function argument positions differ, you'll need some special var in your module to signal where to inject the list.

  arrow(my_list [map map_func arrow.list_here])

Won't be surprised if something like this already exists, but I can't think of keywords to search for that aren't too generic.

> But I also would like to be able to call .sum() on my iterable at the end of a chain

Yeah, one thing I like about Ruby over Python is the fluent code th former allows of that style.

People talk about Guido not liking functional style, but that explains comprehensions over map/filter, but not function-sum() over method .sum().