def METHOD_NAME(unpack_root, prune_list):
    """
    Delete files under unpack_root listed in prune_list. Returns an iterable of unremovable files.
    unpack_root is a pathlib.Path to the directory to be pruned
    prune_list is an iterable of files to be removed.
    """
    unremovable_files = set()
    for relative_file in prune_list:
        file_path = unpack_root / relative_file
        try:
            file_path.unlink()
        # read-only files can't be deleted on Windows
        # so remove the flag and try again.
        except PermissionError:
            os.chmod(file_path, stat.S_IWRITE)
            file_path.unlink()
        except FileNotFoundError:
            unremovable_files.add(Path(relative_file).as_posix())
    return unremovable_files