code: def test_ad_config_none():
      """Tests `ADConfig` initialization when input is None."""
      ad_config_none = ADConfig(None)
      ad_config = ADConfig()
      assert_equal_ad_config(ad_config_none, ad_config)
  
file_path: greykite/greykite/tests/detection/detector/test_config.py
imports: import json
  import pytest
  from greykite.detection.detector.config import ADConfig
  from greykite.detection.detector.config import assert_equal_ad_config
  from greykite.detection.detector.config_utils import AD_CONFIG_JSON_COMPLETE
  from greykite.detection.detector.config_utils import AD_CONFIG_JSON_DEFAULT
  from greykite.detection.detector.config_utils import AD_CONFIG_JSON_PARTIAL
label_desc: Use image node_id 2 for calling a global function with example usage: test_ad_config_none() without return types