docs: def handle(self, *args, **options):
          """ Purge notifications """
          # retrieve layers
          notifications = self.retrieve_old_notifications()
          count = len(notifications)
  
          if count > 0:
              self.output('found %d notifications to purge...' % count)
              notifications.delete()
              self.output('%d notifications deleted successfully.' % count)
          else:
              self.output('there are no old notifications to purge')