Variable orConst

or: {
    <T1, T2>(
        guard1: TypeGuard<T1>,
        guard2: TypeGuard<T2>,
    ): TypeGuard<T1 | T2>;
    <TGuards extends TypeGuards<any>>(
        ...guards: TGuards,
    ): TypeGuard<TUnion<GetTypeGuards<TGuards>>>;
} & { optional: OptionalizedOr } = ...