apply_many.py

def apply_many(f):
    """Write a generator function apply_many that takes in a one-argument function f and at the nth yield, 
    it yields a fcuntion that applies f n times. For example, it first yield f(), f(f()), f(f(f())), etc ...

    >>> f = lambda x: x*2
    >>> gen = apply_many(f)
    >>> [next(gen)(1) for _ in range(3)]
    [2, 4, 8]
    """
    yield f
    for func in apply_many(f):
        yield lambda arg: f(func(arg))