def METHOD_NAME(self, df, gridsize):
    ori = "y"
    df = df[[ori]]
    gb = self.get_groupby(df, ori)
    res = KDE(gridsize=gridsize)(df, gb, ori, {})
    if gridsize is None:
        assert_array_equal(res[ori], df[ori])
    else:
        assert len(res) == gridsize