code: def test_unimplemented_pixel_format():
      with pytest.raises(NotImplementedError):
          with Image.open(
              "Tests/images/unimplemented_pixel_format.dds"
          ):
              pass
  
imports: from io import BytesIO
  import pytest
  from PIL import DdsImagePlugin, Image
  from .helper import assert_image_equal, assert_image_equal_tofile, hopper
label_desc: Use image node_id 16 for calling a global function with example usage: test_unimplemented_pixel_format() without return types