old_contents: from datetime import date
  
  from base import Calendar
  from date import InvalidDate
  from main import JulianCalendar
  
  class JulianToGregorianCalendar(Calendar):
      def date(self, year, month, day):
          gregorian_date = date(year, month, day)
          if gregorian_date < self.first_gregorian_day:
              julian_date = JulianCalendar().date(year, month, day)
              if not julian_date < self.first_gregorian_day:
                  raise InvalidDate("This is a 'missing day' when the calendars changed.")
              self.bless(julian_date)
              return julian_date
          return self.from_date(gregorian_date)
  
      def bless(self, date):
          date.calendar = self.__class__
  
  class EnglishHistoricalCalendar(JulianToGregorianCalendar):
      first_gregorian_day = date(1752, 9, 14)
  
  class SpanishHistoricalCalendar(JulianToGregorianCalendar):
      first_gregorian_day = date(1582, 10, 15)
  
  class FrenchHistoricalCalendar(JulianToGregorianCalendar):
      first_gregorian_day = date(1582, 12, 20)
  
  
new_contents: from datetime import date
  
  from base import Calendar
  from date import InvalidDate
  from main import JulianCalendar
  
  class JulianToGregorianCalendar(Calendar):
      def date(self, year, month, day):
          gregorian_date = date(year, month, day)
          if gregorian_date < self.first_gregorian_day:
              julian_date = JulianCalendar().date(year, month, day)
              if not julian_date < self.first_gregorian_day:
                  raise InvalidDate("This is a 'missing day' when the calendars changed.")
              self.bless(julian_date)
              return julian_date
          return self.from_date(gregorian_date)
  
      def bless(self, date):
          date.calendar = self.__class__
  
  class EnglishHistoricalCalendar(JulianToGregorianCalendar):
      display_name = "English Historical Calendar"
      first_gregorian_day = date(1752, 9, 14)
  
  class SpanishHistoricalCalendar(JulianToGregorianCalendar):
      display_name = "Spanish Historical Calendar"
      first_gregorian_day = date(1582, 10, 15)
  
  class FrenchHistoricalCalendar(JulianToGregorianCalendar):
      display_name = "French Historical Calendar"
      first_gregorian_day = date(1582, 12, 20)
  
  
subject: Add display names to historical calendars.