def METHOD_NAME(self, doi, format):
    if doi.startswith("10.1016/a.test"):
        return f"@article{{DUMMY_KEY,\n\tdoi = {doi}, \n\ttitle = PLACEHOLDER FOR {doi} in {format} format }}"
    try:
        from habanero import cn
    except ImportError:
        raise ImportError(
            "Printing citations require the `habanero` CrossRef API package. Install with `pip install habanero`"
        )
    return cn.content_negotiation(ids=doi, format=format)