If you look through the source for PyExc, you'll find items for (over and above OsError) ValueError, NotImplementedError, TypeError, OverflowError, AttributeError, MemoryError, UnicodeEncodeError, and RuntimeWarning. I don't think ANY of those are documented so are we going to fix them all? Or should we just list them as possibilities in the doco (or, even more vaguely, state that exceptions other than the documented SSL ones are also possible)?