traverse with the identity reverses the nested typ...

# arrow

[raulraja]

traverse with the identity reverses the nested type constructors. It's expressed in Foldable and if that Optional was arrow.core.Option this is what it would look like:

import arrow.*
import arrow.core.*
import arrow.data.*
import arrow.syntax.option.*

val input: List<Option<Int>> = listOf(1.some())
val output: Option<List<Int>> = input.k().traverse(::identity, Option.applicative()).list