val (>>=) : 'a t -> ( 'a -> 'b t ) -> 'b t
val map : ( 'a -> 'b ) -> 'a t -> 'b t
val filter_map : ( 'a -> 'b option ) -> 'a t -> 'b t
val iter : ( 'a -> unit ) -> 'a t -> unit
val fold : ( 'b -> 'a -> 'b ) -> 'b -> 'a t -> 'b
val to_list : 'a t -> 'a list