from typing import Optional


def ad_hoc_fixup(filename: Optional[str], turtle: str) -> str:
    """
    Make any ad-hoc fixes in the source RDF
    :param filename: Name of file being converted
    :param turtle: File value
    :return: tweaked value
    """
    if filename and 'plandefinition-example-cardiology-os' in filename:
        return turtle.replace('a sct:look up value;', 'a sct:look%20up%20value;')
    return turtle