-val fold: ?prefix:string -> ('a -> string -> string -> 'a) -> 'a -> 'a
-val iter: ?prefix:string -> (string -> string -> unit) -> unit
-val to_list: ?prefix:string -> unit -> (string * string) list
+ (** @param interpolate defaults to true *)
+val fold:
+ ?prefix:string -> ?interpolate:bool ->
+ ('a -> string -> string -> 'a) -> 'a -> 'a
+
+ (** @param interpolate defaults to true *)
+val iter:
+ ?prefix:string -> ?interpolate:bool ->
+ (string -> string -> unit) -> unit
+
+ (** @param interpolate defaults to true *)
+val to_list:
+ ?prefix:string -> ?interpolate:bool ->
+ unit -> (string * string) list