>>> from types import new_class
>>> from datetime import datetime
>>> new_class('tdatetime', (datetime, ), kwds={'foo':'bar'})
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/src/Python-3.Lib/types.py", line 52, in new_class
    return meta(name, bases, ns, **kwds)
TypeError: type() takes 1 or 3 arguments

I'm guessing ns and kwds should be combined before being passed through to meta? (meta is 'type' in this case)