def pack_cache_path(root, log_param):
    """generate cache file path

    Parameters
    ----------
    root : str
        cache directory
    log_param : Param

    Returns
    -------
    cache_path : str
        cache fiel path of log_param
    """
    str_log_param = "_".join(map(str, log_param))
    cache_path = f"{root}/{str_log_param}.pickle"
    return cache_path