No one is particularly fond of littering their code with trys and is_a?s. To remedy this, I make my models assert confidence that the data in my database is what I expect. I’m not talking about type coercion, type casting or any other munging of types that might happen on a typical read/write from your handy dandy ORM of choice. No no, this is the real deal, the bees knees, the elbows of a gazelle: actual type validation.