code: def test_merge_cfg_from_file(self):
      with tempfile.NamedTemporaryFile() as f:
          yaml.dump(cfg, f)
          s = cfg.MODEL.TYPE
          cfg.MODEL.TYPE = "dummy"
          assert cfg.MODEL.TYPE != s
          core_config.merge_cfg_from_file(f.name)
          assert cfg.MODEL.TYPE == s
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import copy
  import tempfile
  import unittest
  import yaml
  from detectron.core.config import cfg
  from detectron.utils.collections import AttrDict
  import detectron.core.config
  import detectron.utils.logging
label_desc: Use image node_id 3 for calling the TestCfg obj's underlying member method code with example usage: obj.test_merge_cfg_from_file() without return types