code: def setUpClass(cls):
      cls.dataset = YouTubeVISDataset(
          ann_file="tests/data/vis_sample.json", dataset_version="2019"
      )
  
imports: from unittest import TestCase
  from mmdet.datasets import YouTubeVISDataset
label_desc: Use image node_id 1 for calling the TestYouTubeVISDataset obj's underlying member method code with example usage: obj.setUpClass(cls) without return types