class_docstr: Tests member functions of ClassyDataset. Note, NotImplemented
  functions are mocked in TestDataset class.
class_docstr_tok: ["Tests","member","functions","of","ClassyDataset",".","Note",",","NotImplemented","functions","are","mocked","in","TestDataset","class","."]
code: def setUp(self):
      self.dataset1 = build_dataset(DUMMY_CONFIG, DUMMY_SAMPLES_1)
      self.dataset2 = build_dataset(DUMMY_CONFIG, DUMMY_SAMPLES_2)
  
imports: import multiprocessing
  import unittest
  import unittest.mock
  import classy_vision.dataset.classy_dataset
  import torch
  from classy_vision.dataset import build_dataset, register_dataset
  from classy_vision.dataset.core import ListDataset
  from test.generic.utils import compare_batches, compare_samples
  from torch.utils.data import DataLoader
label_desc: Use image node_id 1 for calling the TestClassyDataset obj's underlying member method code with example usage: obj.setUp() without return types