assertThat(multimap.get("google")).containsExactly(6, 2).inOrder();
    assertThat(multimap.get("tree")).containsExactly(null, 0).inOrder();
  }

  public void testOrderedKeySet() {
    TreeMultimap<@Nullable String, @Nullable Integer> multimap = createPopulate();
    assertThat(multimap.keySet()).containsExactly(null, "tree", "google").inOrder();
  }