@CheckForNull Comparator<? super V> valueComparator) {
    if (mapEntries.isEmpty()) {
      return of();
    }
    ImmutableMap.Builder<K, ImmutableList<V>> builder =
        new ImmutableMap.Builder<>(mapEntries.size());
    int size = 0;

    for (Entry<? extends K, ? extends Collection<? extends V>> entry : mapEntries) {
      K key = entry.getKey();

    @Override
    public ImmutableSetMultimap<K, V> build() {
      Collection<Map.Entry<K, Collection<V>>> mapEntries = builderMap.entrySet();
      if (keyComparator != null) {
        mapEntries = Ordering.from(keyComparator).<K>onKeys().immutableSortedCopy(mapEntries);
      }
      return fromMapEntries(mapEntries, valueComparator);
    }
  }

  /**