Memoization in one line

The memoization decorator in the Python Decorator Library has served me well, but, after reading stupid lambda tricks, I started thinking about how it could be reduced to a single expression. This is the result:

memoize = lambda f: (lambda d={}: lambda *a: d.setdefault(a, a in d or f(*a)))()

Unlike the original, mine doesn’t catch the case of the memoized function being called with unhashable (mutable) arguments. It doesn’t seem like that is a likely scenario, though.

Here is another version which also works with functions taking named arguments:

memo_with_named_args = lambda f: (lambda d={}: lambda *a,**kw: \
    (lambda *k: d.setdefault(k, k in d or f(*a,**kw)))(tuple(kw.items()),a) )()