code: def _main_loop(self):
          '''
          Main loop for the stats collector
          '''
          while self.active:
              self.expire()
              if self.roll and self.is_expired():
                  self.start_time = self.start_time + self.window
                  self._set_key()
              self.purge_old()
              time.sleep(self.cycle_time)
          self._clean_up(f _main_loop(self):
          '''
          Main loop for the stats collector
          '''
          while self.active:
              self.expire()
              if self.roll and self.is_expired():
                  self.start_time = self.start_time + self.window
                  self._set_key()
              self.purge_old()
              time.sleep(self.cycle_time)
          self._clean_up()
docs: Main loop for the stats collector