Yes, itertools is great. But its stblib is still much lighter than Scala's and Ruby's.

Actually, that seems to be the direction/principle of Python, where it is less inclined to add a helper function.

"It has been discussed ad nauseam on comp.lang.python. People seem to enjoy writing their own versions of flatten more than finding legitimate use cases that don't already have trivial solutions." from https://softwareengineering.stackexchange.com/questions/2542...

Not that this is better or worse. It's just that, on the brevity aspect, Python code is gonna be longer.