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(