docstr: predict action by model
          
docstr_tok: ["predict","action","by","model"]
code: def predict(self, obs):
      """predict action by model"""
      obs = paddle.to_tensor(obs.reshape(1, -1), dtype="float32")
      act = self.alg.predict(obs)
      act_numpy = act.detach().cpu().numpy().flatten()
      return act_numpy
  
file_path: PARL/examples/MADDPG/simple_agent.py
imports: import parl
  import paddle
  import numpy
  from parl.utils import ReplayMemory
label_desc: Use image node_id 2 for calling the MAAgent obj's underlying member method code with example usage: obj.predict(obs) and returns: act_numpy