code: def data(self):
      if self._data is None:
          self._data = h5py.File(
              os.path.join(self.root, self.filename), "r"
          )
      return self._data
  
imports: import numpy
  import os
  import json
  import h5py
  from PIL import Image
  from torchvision.datasets.utils import check_integrity, download_url
  from torchmeta.utils.data import Dataset, ClassDataset
label_desc: Use image node_id 4 for calling the CIFAR100ClassDataset obj's underlying member method code with example usage: obj.data() and returns: self