._StoreAction: ClassType

.ArgumentParser!: ClassType
.new = 'ArgumentParser': (description := Str, prog := Str) -> .ArgumentParser!
.ArgumentParser!.
    add_argument!: (
        name: Str, # TODO: var-args
        action := Str or NoneType,
        default := Obj or NoneType,
        type := Type,
        required := Bool,
        help := Str or NoneType,
        choices := Obj or NoneType,
    ) => ._StoreAction
    .parse_args!: (args := Str or [Str; _] or NoneType,) => Obj # TODO: type with dependent types