def METHOD_NAME(df: pd.DataFrame, regions: Table) -> pd.DataFrame:
    """
    Calculate global total of cholera cases and add it to the existing dataset
    """
    countries = regions[regions["region_type"] == "country"]["name"].to_list()
    manual_countries_to_allow = ["Serbia and Montenegro (former)"]
    countries = countries + manual_countries_to_allow
    assert all(
        df["country"].isin(countries)
    ), f"{df['country'][~df['country'].isin(countries)].drop_duplicates()}, is not a country"
    df_glob = df.groupby(["year"]).agg({"cholera_reported_cases": "sum", "cholera_deaths": "sum"}).reset_index()
    df_glob["country"] = "World"
    df_glob["cholera_case_fatality_rate"] = (df_glob["cholera_deaths"] / df_glob["cholera_reported_cases"]) * 100
    df = pd.concat([df, df_glob])
    return df