@Override
    public void serialize(Asn1OutputStream out, BigInteger obj) {
        out.write(BCD.encode(obj));
    }
@Test
    public void shouldSerialize() {
        assertArrayEquals(
            new byte[] { 0x13, 0x37 },
            serialize(new BcdConverter(), BigInteger.class, BigInteger.valueOf(1337))
        );
    }