Is there a standard class for an infinitely nested defaultdict?

Does anyone know if there's a standard class for an infinitely nestable dictionary in Python?

I'm finding myself repeating this pattern:

d = defaultdict(lambda: defaultdict(lambda: defaultdict(int)))
d['abc']['def']['xyz'] += 1

If I want to add "another layer" (e.g. d['abc']['def']['xyz']['wrt']), I have to define another nesting of defaultdicts.

To generalize this pattern, I've written a simple class that overrides __getitem__ to automatically create the next nested dictionary.

e.g.

d = InfiniteDict(('count',0),('total',0))
d['abc']['def']['xyz'].count += 0.24
d['abc']['def']['xyz'].total += 1
d['abc']['def']['xyz']['wrt'].count += 0.143
d['abc']['def']['xyz']['wrt'].total += 1

However, does anyone know of a pre-existing implementation of this idea? I've tried Googling, but I'm not sure what this would be called.