text: from convlab2.policy.dqn import DQN
  import os
  import json
  
  class DQNPolicy(DQN):
      def __init__(self,
                  is_train=False,
                  dataset="Multiwoz",
                  archive_file="",
                  model_file="https://convlab.blob.core.windows.net/convlab-2/dqn_policy_multiwoz.zip"):
          super().__init__(is_train=is_train, dataset=dataset)
          with open(os.path.join(os.path.dirname(os.path.abspath(__file__)), 'config.json'), 'r') as f:
              cfg = json.load(f)
          self.load(cfg['load'])