val add : 'a t -> int -> int -> int -> int -> int -> int -> 'a -> unit
val dummy : 'a t -> 'a
val iteri : (int -> int -> int -> int -> int -> int -> 'a -> bool -> unit) -> 'a t -> unit
val add : 'a t -> int -> int -> int -> int -> int -> int -> 'a -> unit
val dummy : 'a t -> 'a
val iteri : (int -> int -> int -> int -> int -> int -> 'a -> bool -> unit) -> 'a t -> unit