Sorry, posted to quickly. Yes your logic is correct about the "logic" of the return, but theirs actually differs in what it returns, and I am guessing it is an important change. Where is this "foo" used? Perhaps its value is used in a way a boolean return couldn't be?
Just a note, with these kind of points it is often worth just opening up a python console and printing out the results. Though I do agree with you, at first look it seems almost redundant to use 1 and 0. Personally haven't seen this before, rather like it! :) -- http://mail.python.org/mailman/listinfo/python-list
