code: def test_init(self):
      model = get_detector_cfg(
          "cornernet/cornernet_hourglass104_8xb6-210e-mstest_coco.py"
      )
      model.backbone.init_cfg = None
  
      from mmdet.registry import MODELS
  
      detector = MODELS.build(model)
      self.assertTrue(detector.bbox_head is not None)
      self.assertTrue(detector.backbone is not None)
      self.assertTrue(not hasattr(detector, "neck"))
  
file_path: mmdetection/tests/test_models/test_detectors/test_cornernet.py
imports: import unittest
  from unittest import TestCase
  import torch
  from mmengine.config import ConfigDict
  from mmdet.structures import DetDataSample
  from mmdet.testing import demo_mm_inputs, get_detector_cfg
  from mmdet.utils import register_all_modules
label_desc: Use image node_id 2 for calling the TestCornerNet obj's underlying member method code with example usage: obj.test_init() without return types