code: def test_init(self, cfg_file):
      model = get_detector_cfg(cfg_file)
      model.backbone.init_cfg = None
  
      from mmdet.registry import MODELS
  
      detector = MODELS.build(model)
      self.assertTrue(detector.backbone)
      self.assertTrue(detector.neck)
      self.assertTrue(detector.mask_head)
      if detector.with_bbox:
          self.assertTrue(detector.bbox_head)
  
file_path: mmdetection/tests/test_models/test_detectors/test_single_stage_instance_seg.py
imports: import unittest
  from unittest import TestCase
  import torch
  from parameterized import parameterized
  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 TestSingleStageInstanceSegmentor obj's underlying member method code with example usage: obj.test_init(cfg_file) without return types