code: def holidays(self, year=None):
          
          if not year:
              year = date.today().year
  
          if year in self._holidays:
              return self._holidays[year]
  
          # Here we process the holiday specific calendar
          temp_calendar = tuple(self.get_calendar_holidays(year))
  
          # it is sorted
          self._holidays[year] = sorted(temp_calendar)
          return self._holidays[year]
docs: Computes holidays (non-working days) for a given year.
          Return a 2-item tuple, composed of the date and a label.