code: def test_upgrade_downgrade_consistency(self):
      cfg = get_cfg()
      # check that custom is preserved
      cfg.USER_CUSTOM = 1
  
      down = downgrade_config(cfg, to_version=0)
      up = upgrade_config(down)
      self.assertTrue(up == cfg)
  
imports: import os
  import tempfile
  import unittest
  import torch
  from omegaconf import OmegaConf
  from detectron2 import model_zoo
  from detectron2.config import configurable, downgrade_config, get_cfg, upgrade_config
  from detectron2.layers import ShapeSpec
  from detectron2.modeling import build_model
label_desc: Use image node_id 1 for calling the TestConfigVersioning obj's underlying member method code with example usage: obj.test_upgrade_downgrade_consistency() without return types