def _load_image_set_index(self):
    """
    Load the indexes listed in this dataset's image set file.
    """
    # Example path to image set file:
    # self._devkit_path + /VOCdevkit2007/VOC2007/ImageSets/Main/val.txt
    image_set_file = os.path.join(self._data_path, 'ImageSets', 'Main',
                                  self._image_set + '.txt')
    
    assert os.path.exists(image_set_file), \
      'Path does not exist: {}'.format(image_set_file)
    with open(image_set_file) as f:
      image_index = [x.strip() for x in f.readlines()]
    return image_index

    Load the indexes listed in this dataset's image set file.
    
lib/datasets/pascal_voc_rbg.py