Progress_bar.Multi
type ('a, 'b) t
val line : 'a Line.t -> (('a -> unit) -> 'b, 'b) t
val lines : 'a Line.t list -> (('a -> unit) list -> 'b, 'b) t
val (++) : ('a, 'b) t -> ('b, 'c) t -> ('a, 'c) t
val blank : ('a, 'a) t