code: def predict(self, obs):
      obs = np.expand_dims(obs, axis=0)
      obs = obs.astype("float32")
      act = self.fluid_executor.run(
          self.pred_program,
          feed={"obs": obs},
          fetch_list=[self.pred_act],
      )[0]
      return act[0]
  
file_path: PARL/benchmark/fluid/MADDPG/simple_agent.py
imports: import numpy
  import parl
  from parl import layers
  from paddle import fluid
  from parl.utils import ReplayMemory
  from parl.utils import machine_info, get_gpu_count
label_desc: Use image node_id 3 for calling the MAAgent obj's underlying member method code with example usage: obj.predict(obs) and returns: act