type 'a iter = ( 'a -> unit ) -> unit
type 'a printer = Stdlib.Format.formatter -> 'a -> unit
module type OrderedType = Stdlib.Map.OrderedType
module type S = sig ... end
module Make
(O : Stdlib.Map.OrderedType) :
S with type 'a t = 'a Stdlib.Map.Make(O).t and type key = O.t