code: def test_init_stacking_regressor():
      """Test init method of StackingRegressor class."""
      with pytest.raises(ValueError):
          stacking_regressor = StackingRegressor(base_estimators=dict())
      with pytest.raises(ValueError):
          stacking_regressor = StackingRegressor(n_folds=dict())
      with pytest.raises(ValueError):
          stacking_regressor = StackingRegressor(copy="True")
      with pytest.raises(ValueError):
          stacking_regressor = StackingRegressor(random_state="1")
      with pytest.raises(ValueError):
          stacking_regressor = StackingRegressor(verbose="True")
      stacking_regressor = StackingRegressor()
      assert len(stacking_regressor.base_estimators) == 3
      assert isinstance(
          stacking_regressor.level_estimator, type(LinearRegression())
      )
      assert stacking_regressor.n_folds == 5
      assert not stacking_regressor.copy
      assert stacking_regressor.random_state == 1
      assert stacking_regressor.verbose
      assert not stacking_regressor._StackingRegressor__fitOK
      assert not stacking_regressor._StackingRegressor__fittransformOK
  
file_path: MLBox/tests/test_stacking_regressor.py
imports: import pytest
  import pandas
  import numpy
  from sklearn.linear_model import LinearRegression
  from mlbox.model.regression.stacking_regressor import StackingRegressor
label_desc: Use image node_id 1 for calling a global function with example usage: test_init_stacking_regressor() without return types