instance (Representable p, Representable q) => Representable (Bifunctor.Product p q)
type Rep (Bifunctor.Product p q) = Functor.Product p q
instance (Corepresentable p, Corepresentable q) => Corepresentable (Bifunctor.Product p q) where
type Rep (Bifunctor.Product p q) = Functor.Sum p q