Example of function composition in python

functional.py

def compose(*funs):
    """ Takes functions as arguments and their composition as a single function. """
    def compose2(f, g):
        return lambda x: f(g(x))
    return reduce(compose2, funs, lambda x: x)

def curry(func):
    """ Currying decorator. """
    def curried(*args, **kwargs):
        if len(args) + len(kwargs) >= func.__code__.co_argcount:
            return func(*args, **kwargs)
        return (lambda *args2, **kwargs2:
                curried(*(args + args2), **dict(kwargs, **kwargs2)))
    return curried

def memoize(f):
    """ Memoization decorator for functions taking one or more arguments.
    :param f: a function
    """

    class MemoDict(dict):
        def __init__(self, f_, **kwargs):
            super().__init__(**kwargs)
            self.f = f_

        def __call__(self, *args):
            return self[args]

        def __missing__(self, key):
            ret = self[key] = self.f(*key)
            return ret

    return MemoDict(f)

def pmap(*args):
    """ Multiprocess map. """
    with Pool(cpu_count()) as p:
        return p.map(*args)