[Haskell-cafe] Unit and pair

Hi café, a quick question. Is there a somewhat standard class like this: class Something c where unit :: c () () pair :: c x y -> c u v -> c (x, u) (y, v) ? I'm using it heavily in my current project, but I don't want to repeat somebody else's work, and it seems general enough to be defined somewhere; but my quick search on Hackage didn't reveal anything. I know about arrows; this, however, is something more general, and it's instances aren't always arrows.