text: import torch
  from ._body import Body
  from .rewards import ClipRewards
  from .vision import FrameStack
  
  class DeepmindAtariBody(Body):
      def __init__(self, agent, lazy_frames=False, episodic_lives=True, frame_stack=4):
          agent = FrameStack(agent, lazy=lazy_frames, size=frame_stack)
          agent = ClipRewards(agent)
          if episodic_lives:
              agent = EpisodicLives(agent)
          super().__init__(agent)
  
  class EpisodicLives(Body):
      def process_state(self, state):
          if not 'life_lost' in state:
              return state
  
          if len(state) == 1:
              if state['life_lost']:
                  return state.update('mask', 0.)
              return state
  
          masks = [None] * len(state)
          life_lost = state['life_lost']
          for i, old_mask in enumerate(state.mask):
              if life_lost[i]:
                  masks[i] = 0.
              else:
                  masks[i] = old_mask
          return state.update('mask', torch.tensor(masks, device=state.device))
  