Fix flake8 issues

Former-commit-id: 3eb73e0948

run.py

@@ -17,11 +17,11 @@ from sklearn.pipeline import FeatureUnion
 from sklearn.pipeline import Pipeline
 
 import bug_features
-from get_bugs import get_bug_fields
 from get_bugs import get_bugs
 from get_bugs import get_labels
 from utils import ItemSelector
 
+
 def go():
     # Get labels.
     classes = get_labels()
@@ -135,5 +135,6 @@ def go():
     print('Recall: {}'.format(metrics.recall_score(y_test, y_pred)))
     print(metrics.confusion_matrix(y_test, y_pred))
 
+
 if __name__ == '__main__':
     go()