[Haskell-beginners] arrow type signature question

[MH]

I am looking at signatures for Arrow and Composable classes and I cannot
understand some of them. Could you please explain me the following:
Let's take for example the following:

class FunAble h => FunDble h where
  resultFun   :: (h b -> h b') -> (h (a->b) -> h (a->b'))

class FunAble h where
  secondFun :: (h b -> h b') -> (h (a,b) -> h (a,b')) -- for 'second'


in the signatures:
resultFun   :: (h b -> h b') -> (h (a->b) -> h (a->b'))
secondFun :: (h b -> h b') -> (h (a,b) -> h (a,b'))

if (h b -> h b') is the input of these functions where does 'a' comes from
in the output?

Thanks,
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.haskell.org/pipermail/beginners/attachments/20101118/09a58b2a/attachment.html