class_docstr: Tests for mt_opt dataset.
code: def setUpClass(cls):
      mt_opt.MtOpt._INPUT_FILE_PREFIX = cls.dummy_data
      mt_opt._NAME_TO_SPLITS["rlds"]["train"] = 1
      super().setUpClass()
  
file_path: datasets/tensorflow_datasets/robotics/mt_opt/mt_opt_test.py
imports: import tensorflow_datasets.public_api
  from tensorflow_datasets.robotics.mt_opt import mt_opt
label_desc: Use image node_id 1 for calling the MtOptTestRlds obj's underlying member method code with example usage: obj.setUpClass(cls) without return types