code: def test_do_fn():
      apply_do_fn = transform_lib.apply_do_fn(fn=duplicate)
      example = {"a": 1}
      assert list(apply_do_fn(example)) == [example, example]
  
file_path: datasets/tensorflow_datasets/core/transform/transform_lib_test.py
imports: import functools
  from typing import Iterator
  import pytest
  from tensorflow_datasets.core.transform import transform_lib
label_desc: Use image node_id 11 for calling a global function with example usage: test_do_fn() without return types