`sig
type base_u
type u
type t = private u
val bounds : base_u bound_t * base_u bound_t
val make : base_u -> t
external extract : t -> u = "%identity"
val map : (base_u -> base_u) -> t -> t option
val map2 : (base_u -> base_u -> base_u) -> t -> t -> t option
val map_exn : (base_u -> base_u) -> t -> t
val map2_exn : (base_u -> base_u -> base_u) -> t -> t -> t
val ( + ) : t -> base_u -> t
val ( - ) : t -> base_u -> t
val ( * ) : t -> base_u -> t
val ( / ) : t -> base_u -> t
val ( +: ) : t -> t -> t
val ( -: ) : t -> t -> t
val ( *: ) : t -> t -> t
val ( /: ) : t -> t -> t
end`