code: def test_config_copy():
      cfg = Config()
      cfg.register_option("a.b.c", 1)
      cfg.redirect_option("a.c", "a.b.c")
  
      target_cfg = Config()
      target_cfg.register_option("a.b.c", -1)
      target_cfg.redirect_option("a.c", "a.b.c")
  
      src_cfg_dict = cfg.to_dict()
      assert src_cfg_dict == {"a.b.c": 1}
  
      target_cfg.update(src_cfg_dict)
      assert target_cfg.a.b.c == 1
  
file_path: mars/mars/tests/test_config.py
imports: import pickle
  import threading
  import pytest
  from ..config import options, option_context, is_integer, is_string, Config
label_desc: Use image node_id 3 for calling a global function with example usage: test_config_copy() without return types