val item : int -> t -> string optionval add : string -> t -> unitval addMany : string array -> t -> unitval contains : string -> t -> boolval forEach : (string -> int -> unit) -> t -> unitval remove : string -> t -> unitval removeMany : string array -> t -> unitval replace : string -> string -> t -> unitval supports : string -> t -> boolval toggle : string -> t -> boolval toggleForced : string -> 'a -> t -> boolval toString : string -> tval setValue : t -> string -> unit