Fix several issues found with flake8 (#1081)

setup.py

@@ -59,7 +59,7 @@ if 'bdist_wheel' not in sys.argv:
 
 # bdist_wheel
 extras_require = {
-    'test':  tests_require,
+    'test': tests_require,
     # https://wheel.readthedocs.io/en/latest/#defining-conditional-dependencies
     ':sys_platform == "win32"': install_requires_win_only,
 }