code: def test_gridsearch(self):
      import sklearn.model_selection as ms
  
      tuned_parameters = {"statsmodel": [sm.OLS, sm.GLS]}
      diabetes = datasets.load_diabetes()
  
      cv = ms.GridSearchCV(
          base.StatsModelsRegressor(sm.OLS),
          tuned_parameters,
          cv=5,
          scoring=None,
      )
      fitted = cv.fit(diabetes.data, diabetes.target)
      self.assertTrue(fitted.best_estimator_.statsmodel is sm.OLS)
  
file_path: pandas-ml/pandas_ml/smaccessors/test/test_base.py
imports: import pytest
  import numpy
  import sklearn.datasets
  import statsmodels.api
  import pandas_ml.smaccessors.base
  import pandas_ml.util.testing
label_desc: Use image node_id 8 for calling the TestBaseRegressor obj's underlying member method code with example usage: obj.test_gridsearch() without return types