etermining the upper threshold
            fpr, tpr, thresholds = metrics.roc_curve(labels, pred, pos_label=1)
            rf = pd.DataFrame(tpr, fpr, columns=[&#39;tpr&#39;]).assign(threshold=thresholds)
            rf.index.name = &#39;fpr&#39;
            rf=rf.reset_index()
            zt = zedstat.processRoc(df=rf, order=3, total_samples=2*calibration_num,
                                    positive_samples=calibration_num, alpha=0.01, prevalence=0.5)
            zt.smooth(STEP=0.001)
            zt.a