code: def test_crowdhuman_init(self):
      dataset = CrowdHumanDataset(
          data_root="tests/data/crowdhuman_dataset/",
          ann_file="test_annotation_train.odgt",
          data_prefix=dict(img="Images/"),
          pipeline=[],
      )
      self.assertEqual(len(dataset), 1)
      self.assertEqual(dataset.metainfo["classes"], ("person",))
  
imports: import unittest
  from mmdet.datasets import CrowdHumanDataset
label_desc: Use image node_id 1 for calling the TestCrowdHumanDataset obj's underlying member method code with example usage: obj.test_crowdhuman_init() without return types