Fix pyflakes and pep8 errors

Use extra asserts to use previously unused variables in tests,
such as `cass` and `response`.

Fix only pyflakes errors in docs/conf.py

tests/unit/test_request.py

@@ -29,9 +29,9 @@ def test_add_header_deprecated():
     ('https://go.com/', 443),
     ('https://go.com:443/', 443),
     ('https://go.com:3000/', 3000),
-    ])
+])
 def test_port(uri, expected_port):
-    req = Request('GET', uri,  '', {})
+    req = Request('GET', uri, '', {})
     assert req.port == expected_port