docstr: self.target_model从self.model复制参数过来，若decay不为None,则是软更新
          
docstr_tok: ["self.target_model\u4eceself.model\u590d\u5236\u53c2\u6570\u8fc7\u6765\uff0c\u82e5decay\u4e0d\u4e3aNone",",","\u5219\u662f\u8f6f\u66f4\u65b0"]
code: def sync_target(self, decay=None, share_vars_parallel_executor=None):
      """self.target_model从self.model复制参数过来，若decay不为None,则是软更新"""
      if decay is None:
          decay = 1.0 - self.tau
      self.model.sync_weights_to(
          self.target_model,
          decay=decay,
          share_vars_parallel_executor=share_vars_parallel_executor,
      )
  
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 6 for calling the DDPG obj's underlying member method code with example usage: obj.sync_target(decay, share_vars_parallel_executor) without return types