def image_path_from_index(self, index):
    """
    Construct an image path from the image's "index" identifier.
    """
    image_path = os.path.join(self._data_path, 'JPEGImages',
                              index + self._image_ext)
    assert os.path.exists(image_path), \
      'Path does not exist: {}'.format(image_path)
    return image_path

    Construct an image path from the image's "index" identifier.
    
lib/datasets/pascal_voc_rbg.py