def get_all_iso3_from_bcg(database):
    """
    check which iso3 country codes are available from the bcg database

    :param database: sql database
        the database containing the bcg data
    :return: list
        all the iso3 strings available from the bcg database
    """

    return database.db_query("bcg", column="ISO_code")["ISO_code"].tolist()