code: def predict(self, obs):
      obs = np.expand_dims(obs, axis=0)
      act_prob = self.fluid_executor.run(
          self.pred_program,
          feed={"obs": obs.astype("float32")},
          fetch_list=[self.act_prob],
      )[0]
      act_prob = np.squeeze(act_prob, axis=0)
      act = np.argmax(act_prob)  # 根据动作概率选择概率最高的动作
      return act
  
file_path: PARL/examples/tutorials/lesson4/policy_gradient/agent.py
imports: import numpy
  import paddle.fluid
  import parl
  from parl import layers
label_desc: Use image node_id 4 for calling the Agent obj's underlying member method code with example usage: obj.predict(obs) and returns: act