def METHOD_NAME():
    df = names_df
    df["cars"] = df["cars"].astype(str)
    df = boxplot(
        df=df,
        groupby=["region"],
        whisker_type=PostProcessingBoxplotWhiskerType.TUKEY,
        metrics=["cars"],
    )
    columns = {column for column in df.columns}
    assert columns == {
        "cars__mean",
        "cars__median",
        "cars__q1",
        "cars__q3",
        "cars__max",
        "cars__min",
        "cars__count",
        "cars__outliers",
        "region",
    }
    assert len(df) == 4