def METHOD_NAME(filename):
    """
    Check if the given file path points to a file inside an existing archive file. Returns first path from the set of
    parent paths that points to an existing file, or `None` if no such path exists (i.e., file is an actual stand-alone
    file).
    """
    for parent in pathlib.Path(filename).parents:
        if parent.is_file():
            return parent
    return None