@Test
public void testLazyFlatMapMultiple() {

  List<Integer> eval = mlazy(asList(1, 2))
          .flatMap(MonadicsTest.<Integer>twice())
          .flatMap(MonadicsTest.<Integer>twice())
          .eval();
  assertArrayEquals(new Integer[]{1, 1, 1, 1, 2, 2, 2, 2}, eval.toArray(new Integer[]{}));
}