code: def __init__(self, num_rows: int, val: str = "") -> None:
      self.num_rows = num_rows
      self.val = val
  
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 to create a new _DummyDataReader object from inherited base classes: IterDataPipe with example: obj = _DummyDataReader(num_rows, val)