I agree. s.a is not sufficient if you want to avoid code repetition.
You'll naturally want use something like s['a'] at some point if you want to write good code and you will also want to rely on the convenient "returns None instead of throwing an exception" facility. There are workarounds for this (personally, I just wrote a wrapper class to go around it so that I could use a natural dictionary notation with keeping the None behavior). As part of your mandate is to support backward compatibility, someone probably relies on that peculiarity at this point, so you are stuck with the behavior of s['a'] throwing an exception the way it is now. Perhaps just make sure the behavior of the storage object is properly documented so that it doesn't catch new people off guard. > Still, it'd make sense for s['a'] to have the same semantics as s.a.
