I do now! I had known (and used) collections.OrderedDict, but had never used defaultdict. Millions of keyerrors later... I clearly am going to have to spend a

I do now! I had known (and used) collections.OrderedDict, but had never used defaultdict. Millions of keyerrors later... I clearly am going to have to spend a few hours today grokking everything that collections.* has to offer. Thanks very much.