@Override
    public String getSignVersion() {
        return "V4";
    }
@Test
    public void testGetSignVersion() {
        DefaultAuthSigner signer = new DefaultAuthSigner();
        String expectedVersion = "V4";
        String actualVersion = signer.getSignVersion();

        // Assert the returned version matches the expected version
        Assertions.assertEquals(expectedVersion, actualVersion);
    }