/// <summary>
        /// Converts the value of the current <see cref="SwedishPersonalIdentityNumber" /> object to its equivalent short string representation.
        /// Format is YYMMDDXSSSC, for example <example>990807-2391</example> or <example>120211+9986</example>.
        /// </summary>
        /// <param name="date">The date to decide wheter the person is older than 100 years. That decides the delimiter (- or +).</param>
        public string ToShortString(DateTime date)
        {
            var dateOfBirth  = SwedishPersonalIdentityNumberDateCalculations.GetDateOfBirth(Year, Month, Day);
            var age          = SwedishPersonalIdentityNumberDateCalculations.GetAge(dateOfBirth, date);
            var delimiter    = age >= 100 ? '+' : '-';
            var twoDigitYear = Year % 100;

            return($"{twoDigitYear:D2}{Month:D2}{Day:D2}{delimiter}{SerialNumber:D3}{Checksum}");
        }
 /// <summary>
 /// Date of birth for the person according to the personal identity number.
 /// Not always the actual date of birth due to lmitied amount of personal identity numbers per day.
 /// </summary>
 public static DateTime GetDateOfBirthHint(this SwedishPersonalIdentityNumber personalIdentityNumber)
 {
     return(SwedishPersonalIdentityNumberDateCalculations.GetDateOfBirth(personalIdentityNumber.Year, personalIdentityNumber.Month, personalIdentityNumber.Day));
 }