private static final ImmutableList<Integer> LIST_WITH_DUPS =
      ImmutableList.of(1, 1, 2, 4, 4, 4, 8);

  private static final ImmutableList<Integer> LIST_WITHOUT_DUPS = ImmutableList.of(1, 2, 4, 8);

  void assertModelAgrees(
      List<Integer> list,
      Integer key,
      int answer,
      KeyPresentBehavior presentBehavior,
      KeyAbsentBehavior absentBehavior) {
    switch (presentBehavior) {
      case FIRST_PRESENT: