val return : 'a -> 'a Lwt.tval return_unit : unit Lwt.tval return_none : 'a option Lwt.tval return_nil : 'a list Lwt.tval return_true : bool Lwt.tval return_false : bool Lwt.tval return_some : 'a -> 'a option Lwt.tval return_ok : 'a -> ('a, 'b) Stdlib.result Lwt.tval return_error : 'e -> ('a, 'e) Stdlib.result Lwt.tval return_ok_unit : (unit, 'e) Stdlib.result Lwt.tval return_ok_true : (bool, 'e) Stdlib.result Lwt.tval return_ok_false : (bool, 'e) Stdlib.result Lwt.tval return_ok_none : ('a option, 'e) Stdlib.result Lwt.tval return_ok_nil : ('a list, 'e) Stdlib.result Lwt.tval let* : 'a Lwt.t -> ('a -> 'b Lwt.t) -> 'b Lwt.tval and* : 'a Lwt.t -> 'b Lwt.t -> ('a * 'b) Lwt.tval let+ : 'a Lwt.t -> ('a -> 'b) -> 'b Lwt.tval and+ : 'a Lwt.t -> 'b Lwt.t -> ('a * 'b) Lwt.tval join : unit Lwt.t list -> unit Lwt.tval all : 'a Lwt.t list -> 'a list Lwt.tval both : 'a Lwt.t -> 'b Lwt.t -> ('a * 'b) Lwt.t