[lclarkmichalek]

I don't really agree. The greatest structure in most of my Haskell programs is some kind of ErrorT or something. That requires me to structure the way I handle IO and the way that Errorable things happen, but beyond that, `a` is just as generic as any Python type. Sure, a lot of libraries do require you to accept certain premises, which may be a problem, but most of them provide ways to break out of their abstractions: ErrorT provides `runErrorT :: (Monad m, Error e) => ErrorT e m a -> m (Either e a)` which allows me to break out very easily, and due to the composable nature of Haskell, even if the library does not provide a function, it is often far from hard to write one yourself.