code: def test_init(self):
      dataset = OpenImagesChallengeDataset(
          data_root="tests/data/OpenImages/",
          ann_file="challenge2019/challenge-2019-train-detection-bbox.txt",
          data_prefix=dict(img="OpenImages/train/"),
          label_file="challenge2019/cls-label-description.csv",
          hierarchy_file="challenge2019/class_label_tree.np",
          meta_file="annotations/image-metas.pkl",
          pipeline=[],
      )
      dataset.full_init()
      self.assertEqual(len(dataset), 1)
      self.assertEqual(dataset.metainfo["classes"], ["Airplane"])
  
file_path: mmdetection/tests/test_datasets/test_openimages.py
imports: import unittest
  from mmdet.datasets import OpenImagesChallengeDataset, OpenImagesDataset
label_desc: Use image node_id 1 for calling the TestOpenImagesChallengeDataset obj's underlying member method code with example usage: obj.test_init() without return types