def METHOD_NAME(working_dir: str) -> str:
    """
    Returns the path to store meta and checkpoint files
    If working_dir is None, creates ./temp_meta/ directory and stores all the
    intermediate meta and checkpoint files
    :param working_dir: working directory
    :return: path to meta file
    """
    if working_dir is not None:
        if not os.path.exists(working_dir):
            raise ValueError(f"working_dir : {working_dir} does not exist")
        meta_path = working_dir
    # create temporary directory './temp_meta/'
    else:
        meta_path = './temp_meta/'
        if not os.path.exists(meta_path):
            os.mkdir(meta_path)
    return meta_path