fixing flake8

Author: antgonza

qiita_db/study.py

@@ -364,8 +364,6 @@ def delete(cls, id_):
         """
         cls._check_subclass()
 
-        study = cls(id_)
-
         conn_handler = SQLConnectionHandler()
         if exists_table('sample_%d' % id_, conn_handler):
             raise QiitaDBError('Study "%s" can not be erased because it has a '

qiita_pet/handlers/study_handlers/description_handlers.py

@@ -654,7 +654,6 @@ def delete_study(self, study, user, callback):
             is done and it fails
         """
         study_id = study.id
-        study_title = study.title
 
         try:
             Study.delete(study_id)

qiita_pet/test/test_study_handlers.py

@@ -392,7 +392,6 @@ def test_delete_study(self):
         self.assertEqual(response.code, 200)
 
         # checking that the action was sent
-        index = response.body.index('Study')
         self.assertIn("Couldn't remove study", response.body)
 
     def test_delete_sample_template(self):