def METHOD_NAME(self, df, cut):
    ori = "y"
    df = df[[ori]]
    gb = self.get_groupby(df, ori)
    res = KDE(cut=cut, bw_method=1)(df, gb, ori, {})
    vals = df[ori]
    bw = vals.std()
    assert res[ori].min() == pytest.approx(vals.min() - bw * cut, abs=1e-2)
    assert res[ori].max() == pytest.approx(vals.max() + bw * cut, abs=1e-2)