flatmap.py

# Python 3 is an iterator-first language.
# `bind` and `join` are reaching wider adoption under the names `flatmap` and `flatten`.

def flatmap(f, xs):
    return (y for x in xs for y in f(x))

def flatten(xs):
    return (y for x in xs for y in x)

# These don't match the `zip(*args)` behavior of `map`, but I have never actually seen that used.