class_docstr: The Model for Atari env
  Args:
      obs_space (Box): observation space.
      act_space (Discrete): action space.
code: def __init__(self, obs_space, act_space):
      super(AtariModel, self).__init__()
  
      self.conv1 = nn.Conv2D(4, 32, 8, stride=4)
      self.conv2 = nn.Conv2D(32, 64, 4, stride=2)
      self.conv3 = nn.Conv2D(64, 64, 3, stride=1)
  
      self.flatten = nn.Flatten()
      self.fc = nn.Linear(64 * 7 * 7, 512)
  
      self.fc_pi = nn.Linear(512, act_space.n)
      self.fc_v = nn.Linear(512, 1)
  
file_path: PARL/examples/PPO/atari_model.py
imports: import parl
  import paddle.nn
  import paddle.nn.functional
label_desc: Use image node_id 1 to create a new AtariModel object from inherited base classes: parl with example: obj = AtariModel(obs_space, act_space)