code: def forward(self, obs, act):
      concat = paddle.concat([obs, act], axis=1)
      hid = F.relu(self.l1(concat))
      Q = self.l2(hid)
      return Q
  
file_path: PARL/examples/tutorials/parl2_dygraph/lesson5/ddpg/model.py
imports: import parl
  import paddle
  import paddle.nn
  import paddle.nn.functional
label_desc: Use image node_id 2 for calling the Critic obj's underlying member method code with example usage: obj.forward(obs, act) and returns: Q