public static Credentials create(ECKeyPair ecKeyPair) {
        String address = Numeric.prependHexPrefix(Keys.getAddress(ecKeyPair));
        return new Credentials(ecKeyPair, address);
    }
@Test
    public void testCredentialsFromString() {
        Credentials credentials = Credentials.create(SampleKeys.KEY_PAIR);
        verify(credentials);
    }