code: def _walk_omniglot_dir(directory):
    
    directory = os.path.join(directory, tf.io.gfile.listdir(directory)[0])
    alphabets = sorted(tf.io.gfile.listdir(directory))
    for alphabet in alphabets:
      alphabet_dir = os.path.join(directory, alphabet)
      characters = sorted(tf.io.gfile.listdir(alphabet_dir))
      for character in characters:
        character_id = int(character[len("character"):]) - 1
        character_dir = os.path.join(alphabet_dir, character)
        images = tf.io.gfile.listdir(character_dir)
        for image in images:
          label, _ = image.split("_")
          label = int(label) - 1
          image_path = os.path.join(character_dir, image)
          yield alphabet, character_id, label, image_path
docs: Walk an Omniglot directory and yield examples.