AttributeError: 'GridSearchCV' object has no attribute 'cv_results_'

Update your scikit-learn, cv_results_ has been introduced in 0.18.1, earlier it was called grid_scores_ and had slightly different structure http://scikit-learn.org/0.17/modules/generated/sklearn.grid_search.GridSearchCV.html#sklearn.grid_search.GridSearchCV

from sklearn.model_selection import GridSearchCV

use this clf.cv_results_