public class DateRange
{
    public DateTime From { get; private set; }
    public DateTime To { get; private set; }

    public DateRange(DateTime from, DateTime to)
    {
        // Self-validating
        if (from > to)
        {
            throw new ArgumentException("From date cannot be after To date.");
        }
        From = from;
        To = to;
    }

    // Behavior-rich
    public bool Includes(DateTime date)
    {
        return date >= From && date <= To;
    }

    public bool OverlapsWith(DateRange other)
    {
        return From <= other.To && To >= other.From;
    }

    // ... (Equals i GetHashCode metode za jednakost po vrednostima)
}