code: def get_classes(self):
      classes_set = set()
      for entry in tf.gfile.ListDirectory(self._labels_path):
          if "_" not in entry:
              continue
          class_name, _ = entry.split("_")
          classes_set.add(class_name)
      all_classes = list(sorted(classes_set))
      return all_classes
  
file_path: luminoth/luminoth/tools/dataset/readers/object_detection/pascalvoc.py
imports: import os
  import tensorflow
  from luminoth.tools.dataset.readers import InvalidDataDirectory
  from luminoth.tools.dataset.readers.object_detection import ObjectDetectionReader
  from luminoth.utils.dataset import read_xml, read_image
label_desc: Use image node_id 3 for calling the PascalVOCReader obj's underlying member method code with example usage: obj.get_classes() and returns: all_classes