code: def test_when_some_base_models_fail_during_prediction_then_ensemble_raises_runtime_error():
      ets = ETSModel(prediction_length=1, freq=DUMMY_TS_DATAFRAME.freq)
      ets.fit(
          train_data=DUMMY_TS_DATAFRAME,
          hyperparameters={"maxiter": 1, "seasonal": None},
      )
      ensemble = TimeSeriesGreedyEnsemble(name="WeightedEnsemble")
      ensemble.model_to_weight = {"ARIMA": 0.5, "ETS": 0.5}
      ets_preds = ets.predict(DUMMY_TS_DATAFRAME)
      with pytest.raises(RuntimeError):
          ensemble.predict(data={"ARIMA": None, "ETS": ets_preds})
  
imports: import pytest
  from autogluon.timeseries.models import ETSModel
  from autogluon.timeseries.models.ensemble.greedy_ensemble import TimeSeriesGreedyEnsemble
  from ..common import DUMMY_TS_DATAFRAME
label_desc: Use image node_id 1 for calling a global function with example usage: test_when_some_base_models_fail_during_prediction_then_ensemble_raises_runtime_error() without return types