@Override
    public @Nullable LongRangeSet tryJoinExactly(@NotNull LongRangeSet other) {
      if (contains(other)) return this;
      if (other.contains(this)) return other;
      // TODO: support some cases
      return null;
    }
@Override
    public @Nullable LongRangeSet tryJoinExactly(@NotNull LongRangeSet other)