I don't think supporting both approaches is worth it; we should just choose one of them. As for which one, I'm torn. The single argument one is the most pragmatic, but changing types like has always bugged me. But as Martin points out, the `raise` syntax supports the class or an instance so there's precedent in regards to exceptions themselves. The parameter name is poorly named if we take it in for the first argument which is unfortunate.

Basically I can't decide. :)