public static String finalSigningKeyStringWithDefaultInfo(String secret, String region) {
        String signDate = LocalDateTime.now(UTC_0).format(V4_SIGN_DATE_FORMATTER);
        return finalSigningKeyString(secret, signDate, region, RamConstants.SIGNATURE_V4_PRODUCE,
                RamConstants.SIGNATURE_V4_METHOD);
    }
@Test
    void testFinalSigningKeyStringWithDefaultInfo() {
        assertNotNull(CalculateV4SigningKeyUtil.finalSigningKeyStringWithDefaultInfo("", "cn-hangzhou"));
    }