A decorator that "caches" results of an arbitrary function based on its arguments.

cache.py

def cache(func):
    saved = {}
    @wraps(func)
    def newfunc(*args):
        if args in saved:
            return newfunc(*args)
        result = func(*args)
        saved[args] = result
        return result
    return newfunc

Example use:

@cache
def web_lookup(url):
    urllib.urlopen(url).read()