public static Ip4Prefix valueOf(int address, int prefixLength) {
        return new Ip4Prefix(Ip4Address.valueOf(address), prefixLength);
    }
@Test(expected = IllegalArgumentException.class)
    public void testInvalidValueOfByteArrayNegativePrefixLengthIPv4() {
        Ip4Prefix ipPrefix;
        byte[] value;

        value = new byte[] {1, 2, 3, 4};
        ipPrefix = Ip4Prefix.valueOf(value, -1);
    }