I'm trying to perform scaling on both y and X before fitting the forecast model. I want to make the scaling transformation optional. However, I encountered an error when performing the grid search above. from sklearn.preprocessing import MinMaxScaler, PowerTransformer, RobustScaler from sktime.performance_metrics.forecasting import MeanSquaredError from sktime.forecasting.statsforecast import StatsForecastAutoARIMA from sktime.forecasting.model_selection import ExpandingWindowSplitter from sktime.forecasting.compose import ForecastingPipeline from sktime.forecasting.fbprophet import Prophet train1 y M0 Delta ds 2022-10 127 249.0 14.0 2022-11 194 298.0 160.0 2022-12 202 269.0 128.0 2023-01 149 215.0 33.0 2023-02 203 198.0 111.0 2023-03 222 259.0 10.0 2023-04 195 232.0 -1.0 2023-05 236 210.0 47.0 2023-06 76 155.0 -12.0 2023-07 204 232.0 101.0 2023-08 231 221.0 -13.0 2023-09 171 196.0 -30.0 2023-10 172 80.0 39.0 2023-11 173 206.0 1.0 2023-12 132 189.0 -8.0 2024-01 165 190.0 50.0 2024-02 93 136.0 0.0 2024-03 105 126.0 45.0 2024-04 99 134.0 18.0 2024-05 121 128.0 12.0 2024-06 109 181.0 0.0 2024-07 183 244.0 7.0 2024-08 159 195.0 27.0 2024-09 147 186.0 -5.0 test1 M0 Delta ds 2024-10 161.0 -10.0 Forecasting Pipeline pipe_y = TransformedTargetForecaster( steps=[ ("scaler", OptionalPassthrough(TabularToSeriesAdaptor(RobustScaler()))), ("forecaster", StatsForecastAutoARIMA(sp=12)), ] ) pipe_X = ForecastingPipeline( steps=[ ("scaler", OptionalPassthrough(TabularToSeriesAdaptor(RobustScaler()))), ("forecaster", pipe_y), ] ) cv1 = ExpandingWindowSplitter(fh=[1], initial_window=train1.shape[0]-3, step_length=1) gscv1 = ForecastingGridSearchCV( forecaster=pipe_X, param_grid=[ { "scaler__passthrough": [True, False], "forecaster__scaler__passthrough": [True, False], "forecaster": [StatsForecastAutoARIMA(sp=12)], }, { "scaler__passthrough": [True, False], "forecaster": [Prophet()], "forecaster__scaler__passthrough": [True, False], "forecaster__seasonality_mode": ['addictive','multiplicative'], "forecaster__changepoint_prior_scale": [0.001, 0.01, 0.1, 0.5], "forecaster__seasonality_prior_scale": [0.01, 0.1, 1.0, 10.0], }, ], cv=cv1, error_score="raise", scoring=MeanSquaredError(square_root=True), ) gscv1.fit(train1['y'], X=train1[features1]) Error Traceback --------------------------------------------------------------------------- _RemoteTraceback Traceback (most recent call last) _RemoteTraceback: """ Traceback (most recent call last): File "c:\Desktop\Waterfall Chart\lib\site-packages\joblib\externals\loky\process_executor.py", line 463, in _process_worker r = call_item() File "c:\Desktop\Waterfall Chart\lib\site-packages\joblib\externals\loky\process_executor.py", line 291, in __call__ return self.fn(*self.args, **self.kwargs) File "c:\Desktop\Waterfall Chart\lib\site-packages\joblib\parallel.py", line 598, in __call__ return [func(*args, **kwargs) File "c:\Desktop\Waterfall Chart\lib\site-packages\joblib\parallel.py", line 598, in <listcomp> return [func(*args, **kwargs) File "c:\Desktop\Waterfall Chart\lib\site-packages\sktime\forecasting\model_selection\_tune.py", line 368, in _fit_and_score forecaster.set_params(**params) File "c:\Desktop\Waterfall Chart\lib\site-packages\sktime\base\_meta.py", line 60, in set_params self._set_params(steps_attr, **kwargs) File "c:\Desktop\Waterfall Chart\lib\site-packages\sktime\base\_meta.py", line 142, in _set_params super().set_params(**params) File "c:\Desktop\Waterfall Chart\lib\site-packages\skbase\base\_base.py", line 398, in set_params unmatched_params = {key: params[key] for key in unmatched_keys} File "c:\Desktop\Waterfall Chart\lib\site-packages\skbase\base\_base.py", line 398, in <dictcomp> unmatched_params = {key: params[key] for key in unmatched_keys} KeyError: 'estimator' """ ... --> 763 raise self._result 764 return self._result 765 finally: KeyError: 'estimator' I'm trying to follow the automl example in the link below: https://www.sktime.net/en/latest/examples/03b_forecasting_transformers_pipelines_tuning.html Continue reading...