> Close this issue for now, until profiler shows me PyDict_XxxxxString.

I like Serhiy's rationale. We should try to avoid PyDict_GetItemString() wheneve possible. If PyDict_GetItemString() becomes a clear bottleneck, we can discuss again optimizing it. But in the meanwhile, I prefer to use anothe rule: an optimization should not modify the behaviour of a function. That's why I didn't optimize OrderedDict.pop() yet (it changed the docstring, AC should be enhanced for this case).

So yeah, let's close this one.