The Hazy Haskell Compiler

I wonder, is the Levity attached to the arrow? In Coalton they attached * to the arrow, like “Int * Char → Int,” or “Int → Char * Text”. I.e one can give multiple inputs and output multiple outputs for a function, but there isn’t a free-standing “a*b”. I find this really neat in a strict language like Coalton. (PureScript has a less neat mechanism, but similar idea.)