code: def _set_key(self):
          '''
          sets the final key to be used currently
          '''
          if self.roll:
              self.date = time.strftime(self.date_format,
                                        time.gmtime(self.start_time))
  
              self.final_key = '{}:{}'.format(self.key, self.date)
          else:
              self.final_key = self.kef _set_key(self):
          '''
          sets the final key to be used currently
          '''
          if self.roll:
              self.date = time.strftime(self.date_format,
                                        time.gmtime(self.start_time))
  
              self.final_key = '{}:{}'.format(self.key, self.date)
          else:
              self.final_key = self.key
docs: sets the final key to be used currently