docstr: assign the parameters of the training network to the target network
          
code: def sync_target(self):
      """assign the parameters of the training network to the target network"""
      self.model.sync_weights_to(self.target_model)
  
file_path: PARL/parl/algorithms/paddle/dqn.py
imports: import copy
  import parl
  import paddle
  from parl.utils.utils import check_model_method
label_desc: Use image node_id 4 for calling the DQN obj's underlying member method code with example usage: obj.sync_target() without return types