def test_empty_subdir2(self):
        self.auth.creds_subdir = None
        try:
            self.auth.load_creds()
        except ValueError:
            pass
        except Exception as e:
            self.fail('Unexpected exception thrown: %s' % e)
        else:
            self.fail('ValueError exception not thrown.')
Setting subdir to `None` should raise an error.
dataset/ETHPy150Open nltk/nltk/nltk/test/unit/test_twitter_auth.py/TestCredentials.test_empty_subdir2