code: def forward(self, obs_n, act_n):
      inputs = paddle.concat(obs_n + act_n, axis=1)
      hid1 = F.relu(self.fc1(inputs))
      hid2 = F.relu(self.fc2(hid1))
      Q = self.fc3(hid2)
      Q = paddle.squeeze(Q, axis=1)
      return Q
  
file_path: PARL/examples/MADDPG/simple_model.py
imports: import parl
  import paddle
  import paddle.nn
  import paddle.nn.functional
label_desc: Use image node_id 2 for calling the CriticModel obj's underlying member method code with example usage: obj.forward(obs_n, act_n) and returns: Q