code: def step(self, action):
      
      total_reward = 0.0
      done = None
      for i in range(self._skip):
        obs, reward, done, info = self.env.step(action)
        if i == self._skip - 2:
          self._obs_buffer[0] = obs
        if i == self._skip - 1:
          self._obs_buffer[1] = obs
        total_reward += reward
        if done:
          break
      # Note that the observation on the done=True frame doesn't matter.
      max_frame = self._obs_buffer.max(axis=0)
      return max_frame, total_reward, done, info
docs: Repeat action, sum reward, and max over last observations.