external add_drive : t -> string -> unit = "ocaml_guestfs_add_drive"
external add_cdrom : t -> string -> unit = "ocaml_guestfs_add_cdrom"
external config : t -> string -> string option -> unit = "ocaml_guestfs_config"
external add_drive : t -> string -> unit = "ocaml_guestfs_add_drive"
external add_cdrom : t -> string -> unit = "ocaml_guestfs_add_cdrom"
external config : t -> string -> string option -> unit = "ocaml_guestfs_config"