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 test_shard_logic(self):
      # This test uses a world size of 2, rank 1 to verify that the
      # second sample is returned by the dataloader
      dataset = TestDataset(DUMMY_SAMPLES_2, batchsize_per_replica=1)
      dl = dataset.iterator(num_workers=0)
      sample = next(iter(dl))
      self._compare_batches(sample, DUMMY_SAMPLES_2[1])
  
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 9 for calling the TestClassyDataset obj's underlying member method code with example usage: obj.test_shard_logic() without return types