docstr: Args:
      obs: A float32 tensor of shape [B, C, H, W]
  
  Returns:
      policy_logits: B * ACT_DIM
code: def policy(self, obs):
      """
      Args:
          obs: A float32 tensor of shape [B, C, H, W]
  
      Returns:
          policy_logits: B * ACT_DIM
      """
      obs = obs / 255.0
      conv1 = self.conv1(obs)
      conv2 = self.conv2(conv1)
      conv3 = self.conv3(conv2)
  
      flatten = layers.flatten(conv3, axis=1)
      fc_output = self.fc(flatten)
  
      policy_logits = self.policy_fc(fc_output)
      return policy_logits
  
file_path: PARL/benchmark/fluid/GA3C/atari_model.py
imports: import parl
  import paddle.fluid
  from parl import layers
label_desc: Use image node_id 2 for calling the AtariModel obj's underlying member method code with example usage: obj.policy(obs) and returns: policy_logits