code: def setUpClass(cls):
      super(ExtractorTest, cls).setUpClass()
      cls.f1_content = _read(os.path.join(cls.test_data, "6pixels.png"))
      cls.f2_content = _read(os.path.join(cls.test_data, "foo.csv"))
  
imports: import os
  from unittest import mock
  import tensorflow
  from tensorflow_datasets import testing
  from tensorflow_datasets.core.download import extractor
  from tensorflow_datasets.core.download import resource
label_desc: Use image node_id 1 for calling the ExtractorTest obj's underlying member method code with example usage: obj.setUpClass(cls) without return types