Added feature stdev_cut to the penalized spline method. The new parameter takes a floating point value. Outliers larger than stdev_cut are removed in each iteration. The threshold is calculated in standard deviations from the mean (after trend fitting). Older versions of wotan had this parameter hardcoded as PSPLINES_STDEV_CUT = 2 . Now it is user variable. If no value is given, it will fall back on the default.