docs: public static int getWorkingDays (@Nonnull final LocalDate aStartDate,
                                      @Nonnull final LocalDate aEndDate,
                                      @Nonnull final IHolidayManager aHolidayMgr)
    {
      ValueEnforcer.notNull (aStartDate, "StartDate");
      ValueEnforcer.notNull (aEndDate, "EndDate");
      ValueEnforcer.notNull (aHolidayMgr, "HolidayMgr");
  
      final boolean bFlip = aStartDate.isAfter (aEndDate);
      LocalDate aCurDate = bFlip ? aEndDate : aStartDate;
      final LocalDate aRealEndDate = bFlip ? aStartDate : aEndDate;
  
      int ret = 0;
      while (!aRealEndDate.isBefore (aCurDate))
      {
        if (isWorkDay (aCurDate, aHolidayMgr))
          ret++;
        aCurDate = aCurDate.plusDays (1);
      }
      return bFlip ? -1 * ret : ret;
    }