@NotNull
  public static DiffIterable createUnchanged(@NotNull List<? extends Range> ranges, int length1, int length2) {
    DiffIterable invert = invert(create(ranges, length1, length2));
    verify(invert);
    return invert;
  }
@NotNull
  public static DiffIterable createUnchanged(@NotNull List<? extends Range> ranges, int length1, int length2)