tree.put(1.0, 2.0);
    tree.put(2.0, 3.0);
    tree.put(3.0, 4.0);
    tree.put(4.0, 5.0);

    SortedSetMultimap<Double, Double> sorted = Multimaps.unmodifiableSortedSetMultimap(tree);
    TreeMultimap<Double, Double> copyFromSorted = TreeMultimap.create(sorted);
    assertEquals(tree, copyFromSorted);
    assertSame(Ordering.natural(), copyFromSorted.keyComparator());

      assertEquals(8, multimap.size());
    }

    Multimap<@Nullable String, @Nullable Integer> unmodifiable;
    if (multimap instanceof SortedSetMultimap) {
      unmodifiable =
          Multimaps.unmodifiableSortedSetMultimap(
              (SortedSetMultimap<@Nullable String, @Nullable Integer>) multimap);
    } else if (multimap instanceof SetMultimap) {
      unmodifiable =
          Multimaps.unmodifiableSetMultimap(