Module Traversable

module Traversable: sig .. end

module type Basic = sig .. end

module type Basic2 = sig .. end

module type Basic3 = sig .. end

module type S = sig .. end

module type S2 = sig .. end

module type S3 = sig .. end

module Make: 
functor (T : Basic) -> S  with
    type 'a t := 'a T.t and
    type 'a f := 'a T.f

module Make2: 
functor (T : Basic2) -> S2  with
    type 'a t := 'a T.t and
    type ('u, 'a) f := ('u, 'a) T.f

module Make3: 
functor (T : Basic3) -> S3  with
    type 'a t := 'a T.t and
    type ('u, 'v, 'a) f := ('u, 'v, 'a) T.f