code: def test(self) -> None:
      datapipe = _DummyDataReader(100).limit(10)
      self.assertEqual(len(list(datapipe)), 10)
  
imports: import random
  import unittest
  from typing import Any, Iterator, List, Tuple
  from unittest.mock import Mock, patch
  from torch.utils.data import IterDataPipe
  from torchrec.datasets.utils import idx_split_train_val, ParallelReadConcat, rand_split_train_val
label_desc: Use image node_id 1 for calling the TestLimit obj's underlying member method code with example usage: obj.test() without return types