public static ComposeCombineFnBuilder compose() {
    return new ComposeCombineFnBuilder();
  }
@Test
  public void testDuplicatedTagsKeyed() {
    expectedException.expect(IllegalArgumentException.class);
    expectedException.expectMessage("it is already present in the composition");

    TupleTag<Integer> tag = new TupleTag<>();
    CombineFns.compose()
        .with(new GetIntegerFunction(), Max.ofIntegers(), tag)
        .with(new GetIntegerFunction(), Min.ofIntegers(), tag);
  }