code: static List<String> integer(String name, @Nullable Integer value) {
      if (value != null) {
        return Arrays.asList("--" + name, value.toString());
      }
      return Collections.emptyList();
    }
docs: Produces the flag form of an integer value using {@link Integer#toString()}.
  
  @return {@code [--name, value]} or {@code []} if value is null.