PEP 3115 introduced keyword arguments to class definitions and changed metaclasses to use them instead. Unfortunately, `type()` doesn't seem to have been updated to accept those keyword arguments as well. What this amounts to is that using `type()` as a constructor can no longer fully replicate the behavior of a class definition. Therefore, classes that use keyword arguments can't be created dynamically.

I would attempt a patch, but I don't have a development environment capable of compiling Python, so I wouldn't have any chance to test it.