def memoize_nonzero(func):
    """
    Memoization decorator for functions taking a nonzero number of arguments.

    References:
        http://code.activestate.com/recipes/578231-fastest-memoization-decorator
    """
    class _memorizer(dict):
        def __init__(self, func):
            self.func = func
        def __call__(self, *args):
            return self[args]
        def __missing__(self, key):
            ret = self[key] = self.func(*key)
            return ret
    return _memorizer(func)
Memoization decorator for functions taking a nonzero number of arguments.

    References:
        http://code.activestate.com/recipes/578231-fastest-memoization-decorator