code: def add_datapath_and_model_args(opt: Opt):
      # add datapath, it is missing
      from parlai.core.params import ParlaiParser, get_model_name
  
      parser = ParlaiParser(add_parlai_args=False)
      parser.add_parlai_data_path()
      # add model args if they are missing
      model = get_model_name(opt)
      if model is not None:
          parser.add_model_subargs(model, opt)
      opt_parser = parser.parse_args("")
      for k, v in opt_parser.items():
          if k not in opt:
              opt[k] = v
  
imports: import copy
  from typing import List, Union
  from parlai.core.build_data import modelzoo_path
  from parlai.core.loader import load_agent_module
  from parlai.core.loader import register_agent
  from parlai.core.message import Message
  from parlai.core.opt import Opt
  from parlai.utils.misc import warn_once
  import parlai.utils.logging
  from parlai.utils.io import PathManager
label_desc: Use image node_id 4 for calling a global function with example usage: add_datapath_and_model_args(opt) without return types