docs: def as_dates(self):
          """
          Create a new DateRange with the datetimes converted to dates and changing to CLOSED/CLOSED.
          """
          new_start = self.start.date() if self.start and isinstance(self.start, datetime.datetime) else self.start
          new_end = self.end.date() if self.end and isinstance(self.end, datetime.datetime) else self.end
          return DateRange(new_start, new_end, CLOSED_CLOSED)