code: 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));
    }
docs: Returns the IPv4 address embedded in an IPv4 compatible address.
  
  @param ip {@link Inet6Address} to be examined for an embedded IPv4 address
  @return {@link Inet4Address} of the embedded IPv4 address
  @throws IllegalArgumentException if the argument is not a valid IPv4 compatible address