code: def test_save():
      # Arrange
      with Image.open(TEST_FILE) as im:
          dummy_fp = None
          dummy_filename = "dummy.filename"
  
          # Act / Assert: stub cannot save without an implemented handler
          with pytest.raises(OSError):
              im.save(dummy_filename)
          with pytest.raises(OSError):
              Hdf5StubImagePlugin._save(im, dummy_fp, dummy_filename)
  
imports: import pytest
  from PIL import Hdf5StubImagePlugin, Image
label_desc: Use image node_id 4 for calling a global function with example usage: test_save() without return types