code: def _sample_len(
      self,
      sample: Dict[str, List[Any]],  # pyre-ignore[2]
  ) -> int:
      return len(next(iter(sample.values())))
  
imports: import contextlib
  import math
  import os
  import random
  import tempfile
  from typing import Any, Dict, List, Optional
  import numpy
  from torch.utils.data import DataLoader
  from torchrec.datasets.criteo import BinaryCriteoUtils, CAT_FEATURE_COUNT, criteo_kaggle, criteo_terabyte, InMemoryBinaryCriteoIterDataPipe, INT_FEATURE_COUNT
  from torchrec.datasets.test_utils.criteo_test_utils import CriteoTest
  from torchrec.datasets.utils import Batch
label_desc: Use image node_id 2 for calling the CriteoDataLoaderTest obj's underlying member method code with example usage: obj._sample_len(sample) and returns: len