def _get_pdiff(example, diff):
    test_png, ref_png, diff_png = get_example_pngs(example, diff)
    info("generated image: " + test_png)

    retrieved_reference_image = _get_reference_image_from_s3(example, diff)

    if retrieved_reference_image:
        ref_png_path = dirname(ref_png)
        if not exists(ref_png_path):
            os.makedirs(ref_png_path)

        with open(ref_png, "wb") as f:
            f.write(retrieved_reference_image)

        info("saved reference: " + ref_png)

        code = process_image_diff(diff_png, test_png, ref_png)
        if code != 0:
            warn("generated and reference images differ")
            warn("diff: " + diff_png)
        else:
            ok("generated and reference images match")
dataset/ETHPy150Open bokeh/bokeh/tests/examples/test_examples.py/_get_pdiff/original