val iter : f:(elt -> unit) -> t -> unit
val fold : f:(elt -> 'a -> 'a) -> t -> init:'a -> 'a
val for_all : f:(elt -> bool) -> t -> bool
val exists : f:(elt -> bool) -> t -> bool
val filter : f:(elt -> bool) -> t -> t
val filter_map : f:(elt -> elt option) -> t -> t
val partition : f:(elt -> bool) -> t -> t * t