}

    return empty
        ? new EmptyContiguousSet<C>(domain)
        : new RegularContiguousSet<C>(effectiveRange, domain);
  }

  /**
   * Returns a nonempty contiguous set containing all {@code int} values from {@code lower}
   * (inclusive) to {@code upper} (inclusive). (These are the same values contained in {@code
   * Range.closed(lower, upper)}.)
   *

    }

    return empty
        ? new EmptyContiguousSet<C>(domain)
        : new RegularContiguousSet<C>(effectiveRange, domain);
  }

  /**
   * Returns a nonempty contiguous set containing all {@code int} values from {@code lower}
   * (inclusive) to {@code upper} (inclusive). (These are the same values contained in {@code
   * Range.closed(lower, upper)}.)
   *