code: def _validate_structure(self):
      if not tf.gfile.Exists(self._data_dir):
          raise InvalidDataDirectory(
              '"{}" does not exist.'.format(self._data_dir)
          )
  
      if not tf.gfile.Exists(self._imagesets_path):
          raise InvalidDataDirectory("ImageSets path is missing")
  
      if not tf.gfile.Exists(self._images_path):
          raise InvalidDataDirectory("Images path is missing")
  
      if not tf.gfile.Exists(self._annotations_path):
          raise InvalidDataDirectory("Annotations path is missing")
  
file_path: luminoth/luminoth/tools/dataset/readers/object_detection/imagenet.py
imports: import json
  import os
  import six
  import tensorflow
  from PIL import Image
  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 5 for calling the ImageNetReader obj's underlying member method code with example usage: obj._validate_structure() without return types