module type Comparable = sig .. end
sig
end
type 'a t
'a
val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
('a -> 'a -> int) -> 'a t -> 'a t -> int
val to_string : ('a -> string) -> 'a t -> string
('a -> string) -> 'a t -> string