def METHOD_NAME(f: str) -> None:
    """Save a mismatched result to tests/actual."""
    save_path = expected_dir.replace(os_sep("/gold/"), os_sep("/actual/"))
    os.makedirs(save_path, exist_ok=True)
    save_file = os.path.join(save_path, f)
    with open(save_file, "w") as savef:
        with open(os.path.join(actual_dir, f)) as readf:
            savef.write(readf.read())
            print(os_sep(f"Saved actual output to '{save_file}': see tests/gold/README.rst"))