@Override
    public List<String> apply(Integer from) {
      String value = String.valueOf(from);
      return ImmutableList.of(value, value);
    }
  }

  public void testTransformAndConcat() {
    List<Integer> input = asList(1, 2, 3);
    Iterable<String> result =
        FluentIterable.from(input).transformAndConcat(new RepeatedStringValueOfFunction());