* @return {@link Inet4Address} of the embedded IPv4 address
   * @throws IllegalArgumentException if the argument is not a valid IPv4 compatible address
   */
  public static Inet4Address getCompatIPv4Address(Inet6Address ip) {
    checkArgument(
        isCompatIPv4Address(ip), "Address '%s' is not IPv4-compatible.", toAddrString(ip));

    return getInet4Address(Arrays.copyOfRange(ip.getAddress(), 12, 16));
  }

      assertThrows(
          "IllegalArgumentException expected for '" + nonCompatAddress + "'",
          IllegalArgumentException.class,
          () -> InetAddresses.getCompatIPv4Address((Inet6Address) ip));
    }

    ImmutableSet<String> validCompatAddresses = ImmutableSet.of("::1.2.3.4", "::102:304");
    String compatStr = "1.2.3.4";
    InetAddress compat = InetAddresses.forString(compatStr);