code: def are_dates(self):
          
          if self.depth != 1:
              return False
          first_cat_label = self[0].label
          date_types = (datetime.date, datetime.datetime)
          if isinstance(first_cat_label, date_types):
              return True
          return False
docs: Return |True| if the first category in this collection has a date
          label (as opposed to str or numeric). A date label is one of type
          datetime.date or datetime.datetime. Returns |False| otherwise,
          including when this category collection is empty. It also returns
          False when this category collection is hierarchical, because
          hierarchical categories can only be written as string labels.