An IndTraversable is a Traversable able to read some extra data, the index.
import public Data.Foldable.Indexedinterface IndTraversable : Type -> (Type -> Type) -> Typeitraverse : Applicative f => (i -> a -> f b) -> t a -> f (t b)IndTraversable () MaybeIndTraversable a (Pair a)IndTraversable Nat ListIndTraversable (Fin k) (Vect k)itraverse : IndTraversable i t => Applicative f => (i -> a -> f b) -> t a -> f (t b)