code: def setUpClass(cls):
      super(SplitsTest, cls).setUpClass()
      tmp_dir = testing.make_tmp_dir()
      cls._builder = testing.DummyDatasetSharedGenerator(
          data_dir=tmp_dir
      )
      cls._builder.download_and_prepare()
  
imports: from tensorflow_datasets import testing
  from tensorflow_datasets.core import naming
  from tensorflow_datasets.core import proto
  from tensorflow_datasets.core import splits
  from tensorflow_datasets.core.utils import shard_utils
  import tensorflow_datasets.public_api
label_desc: Use image node_id 1 for calling the SplitsTest obj's underlying member method code with example usage: obj.setUpClass(cls) without return types