public static Formatter forNumbers(@Nonnull String format) {
        return new NumberFormat(format);
    }
@Test
    public void testRomanNumerals() {
        Formatter f = forNumbers("FMRN");
        check(485, f, "CDLXXXV");

        f = forNumbers("RN");
        check(485,  f, "        CDLXXXV");
        check(3888, f, "MMMDCCCLXXXVIII");
    }