@J2ktIncompatible // serialization
    @GwtIncompatible // serialization
    Object writeReplace() {
      return super.writeReplace();
    }
  }

  static <R, C, V> RegularImmutableTable<R, C, V> forCells(
      List<Cell<R, C, V>> cells,
      @CheckForNull Comparator<? super R> rowComparator,
      @CheckForNull Comparator<? super C> columnComparator) {
    checkNotNull(cells);