docstr: 使用 self.model 的 actor model 来预测动作
          
docstr_tok: ["\u4f7f\u7528","self.model","\u7684","actor","model","\u6765\u9884\u6d4b\u52a8\u4f5c"]
code: def predict(self, obs):
      """使用 self.model 的 actor model 来预测动作"""
      return self.model.policy(obs)
  
file_path: PARL/examples/tutorials/lesson5/ddpg/algorithm.py
imports: import parl
  from parl import layers
  from copy import deepcopy
  from paddle import fluid
label_desc: Use image node_id 2 for calling the DDPG obj's underlying member method code with example usage: obj.predict(obs) and returns: self