Ok, of course that was using the trunk version, but the behavior is the same for the Leopard stock install:
>>> m._.transform = t
Traceback (most recent call last):
File "", line 1, in
File "/System/Library/Frameworks/Python.framework/Versions/2.5/Extras/lib/python/PyObjC/objc/_convenience.py", line 141, in __setattr__
return self.__object.setValue_forKey_(value...
2009-02-09 18:21:40 UTC in PyObjC