I have a subclass of dict where __getitem__ returns None rather than raising KeyError for missing keys. (The why of that is not important for this question.)
I was delighted to find that __contains__ still works as before after overriding __getitem__. So even though instance['key'] does not raise KeyError, I still get (as desired) 'key' in instance == False. Looking forward: Can I count on this independence of __getitem__ and __contains__? I would like to understand whether it will be safe to count on this behavior. Thank you, Alan Isaac -- http://mail.python.org/mailman/listinfo/python-list
