code: def _generate_examples(self, archive, validation_labels=None):
      
      if validation_labels:  # Validation split
        for example in self._generate_examples_validation(archive,
                                                          validation_labels):
          yield example
      # Training split. Main archive contains archives names after a synset noun.
      # Each sub-archive contains pictures associated to that synset.
      for fname, fobj in archive:
        label = fname[:-4]  # fname is something like 'n01632458.tar'
        # TODO(b/117643231): in py3, the following lines trigger tarfile module
        # to call `fobj.seekable()`, which Gfile doesn't have. We should find an
        # alternative, as this loads ~150MB in RAM.
        fobj_mem = io.BytesIO(fobj.read())
        for image_fname, image_fobj in tfds.download.iter_archive(
            fobj_mem, tfds.download.ExtractMethod.TAR):
          yield {
              'file_name': image_fname,
              'image': image_fobj,
              'label': label,
          }
docs: Yields examples.