class_docstr: Dataset Loader for classification models.
code: def num_classes(self: ds._DatasetT) -> int:
      return len(self._label_names)
  
file_path: mediapipe/mediapipe/model_maker/python/core/data/classification_dataset.py
imports: from typing import List, Optional, Tuple
  import tensorflow
  from mediapipe.model_maker.python.core.data import dataset
label_desc: Use image node_id 2 for calling the ClassificationDataset obj's underlying member method code with example usage: obj.num_classes() and returns: len