"I would never join a club that would accept me as member"
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This guy's ahead of his time! He's using quantum programming methods: in universes where invalid data is passed to this function, it does not return. Thus you are ensured that you will only have valid data after calling it. Optimally you'd destroy the universe on failure, but computers haven't quite advanced to that level yet.
-- [link|http://thedailywtf.com/archive/2004/10/26/2920.aspx|The] Daily WTF