code: public static void acceptsHex(OptionParser parser) {
          parser.acceptsAll(Arrays.asList(OPT_X, OPT_HEX), "fetch key/entry by key value of hex type")
                .withRequiredArg()
                .describedAs("key-list")
                .withValuesSeparatedBy(',')
                .ofType(String.class);
      }
docs: Adds OPT_X | OPT_HEX option to OptionParser, with multiple arguments.
  
  @param parser OptionParser to be modified
  @param required Tells if this option is required or optional