let P =
      https://prelude.dhall-lang.org/v20.1.0/package.dhall
        sha256:26b0ef498663d269e4dc6a82b0ee289ec565d683ef4c00d0ebdd25333a5a3c98

let cat = ../../Category/Cat/semigroupal

let vObject = Type

let Set =
      ../../Category/Monoidal/Cartesian/extractCategory
        cat
        vObject
        Type
        ../../Category/Set/monoidal/cartesian

let v = Set

in    { map =
          λ(a : Type) →
          λ(b : Type) →
          λ(f : a → Optional b) →
          λ(l : List a) →
            List/fold
              a
              l
              (List b)
              ( λ(x : a) →
                λ(acc : List b) →
                  P.Optional.fold b (f x) (List b) (λ(y : b) → [ y ] # acc) acc
              )
              ([] : List b)
      }
    : ../../Functor/Star/Type vObject Type v Set Optional List