code: def reward_battery(self):
          
          if not 'battery' in self.mode:
              return
          mode = self.mode['battery']
          if mode and mode and self.__test_cond(mode):
              self.logger.debug('Battery out')
              self.player.stats['reward'] += mode['reward']
  
              self.player.game_over = self.player.game_over or mode['terminal']
docs: Add a battery level reward