python中的递归memoize加速

def memoize(f):
    cache = {}
    def memoized(*args):
        if args in cache:
            return cache[args]
        else:
            cache[args] = f(*args)
            return cache[args]
    return memoized

@memoize
def f(n):
    if n <= 1:
        return n
    else:
        return f(n - 1) + f(n - 2)