code: def num_classes(self):
      return self._num_classes
  
imports: import numpy
  from PIL import Image
  import h5py
  import json
  import os
  import io
  import pickle
  from torchmeta.utils.data import Dataset, ClassDataset, CombinationMetaDataset
  from torchmeta.datasets.utils import download_file_from_google_drive
label_desc: Use image node_id 5 for calling the TieredImagenetClassDataset obj's underlying member method code with example usage: obj.num_classes() and returns: self