Traceback (most recent call last):


 "main.py", line 30, in <module>

trio.run(async_main)


 "/.../site-packages/trio/_core/_run.py", line 1337, in run

raise runner.main_task_outcome.error


 "main.py", line 27, in async_main

raise


 "/.../site-packages/trio/_core/_ki.py", line 165, in wrapper

return fn(*args, **kwargs)


 "/.../site-packages/trio/_core/_run.py", line 260, in __exit__

raise remaining_error_after_cancel_scope


 "main.py", line 20, in async_main

await trio.sleep_forever()


 "/.../site-packages/trio/_core/_run.py", line 397, in __aexit__

raise combined_error_from_nursery


 "main.py", line 8, in raiser

raise ValueError('foo')
ValueError: foo

`Traceback (most recent call last):



 "<ipython-input-362-6ef348c52370>", line 1, in <module>

forecaster.fit(y_train)



 "/Users/muhlbach/opt/anaconda3/envs/experimental/lib/python3.8/site-packages/sktime/forecasting/theta.py", line 131, in fit

super(ThetaForecaster, self).fit(y, fh=fh)



 "/Users/muhlbach/opt/anaconda3/envs/experimental/lib/python3.8/site-packages/sktime/forecasting/base/adapters/_statsmodels.py", line 47, in fit

self._fit_forecaster(y, X)



 "/Users/muhlbach/opt/anaconda3/envs/experimental/lib/python3.8/site-packages/sktime/forecasting/exp_smoothing.py", line 79, in _fit_forecaster

self._forecaster = _ExponentialSmoothing(



 "/Users/muhlbach/opt/anaconda3/envs/experimental/lib/python3.8/site-packages/pandas/util/_decorators.py", line 199, in wrapper

return func(*args, **kwargs)



 "/Users/muhlbach/opt/anaconda3/envs/experimental/lib/python3.8/site-packages/statsmodels/tsa/holtwinters/model.py", line 291, in __init__

self._initialize()



 "/Users/muhlbach/opt/anaconda3/envs/experimental/lib/python3.8/site-packages/statsmodels/tsa/holtwinters/model.py", line 439, in _initialize

raise ValueError(msg.format("level"))

ValueError: initialization method is estimated but initial_level has been set.`
