PyObjC, you are so helpful:
"Expecting instance of reply_fixer as self, got one of reply_fixer"
That doesn't seem like a reason to throw an exception to me.
I'm pretty close to just giving up on python for this and using Objective-C instead (even though part of the reason why I'm doing this is to play with python some more).
Uh. I like shiny things? :-)