code: def __len__(self):
      return self.data.shape[0]
  
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 2 for calling the CIFAR100Dataset obj's underlying member method code with example usage: obj.__len__() and returns: self