code: def test_write_format_warning(test_images):
      frames = iio.imread(test_images / "chelsea.png")
      bytes_image = iio.imwrite(
          "<bytes>", frames, extension=".png", plugin="pillow"
      )
  
      with pytest.warns(UserWarning):
          old_bytes = iio.imwrite(
              "<bytes>", frames, plugin="pillow", format="PNG"
          )
  
      assert bytes_image == old_bytes
  
imports: import io
  import os
  from pathlib import Path
  import imageio.v3
  import numpy
  import pytest
  from imageio.core.request import InitializationError, Request
  from imageio.core.v3_plugin_api import PluginV3
  from imageio.plugins.pillow import PillowPlugin
  from PIL import Image, ImageSequence, ImageOps, __version__
label_desc: Use image node_id 37 for calling a global function with example usage: test_write_format_warning(test_images) without return types