def info(df, id_num):
    """
    :param df: the dataframe of 'nations.csv'
    :param id: the id of nation
    :return: a tuple - (string country name, string country
    code, string continent)
    """
    try:
        target = df[df['nationID'] == id_num]
    except KeyError:
        print('Nation ID:' + id_num + ' not exists!')
        raise KeyError()

    name = target['nationName'].tolist()
    code = target.nationCode.tolist()
    continent = target.continent.tolist()

    return (name[0], code[0], continent[0])