module type Basic = sig .. end
sig
end
type '_ t
'_
type '_ f
val traverse : ('a -> 'b f) -> 'a t -> 'b t f
('a -> 'b f) -> 'a t -> 'b t f
val traverse_ : ('a -> 'b f) -> 'a t -> unit f
('a -> 'b f) -> 'a t -> unit f