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