}

  @Override
  public boolean equals(@CheckForNull Object object) {
    if (object == this) {
      return true;
    } else if (object instanceof RegularContiguousSet) {
      RegularContiguousSet<?> that = (RegularContiguousSet<?>) object;
      if (this.domain.equals(that.domain)) {
        return this.first().equals(that.first()) && this.last().equals(that.last());
      }
    }