[Py] setup.py code style formatting. (#2164)

* Uniform quotes style .

* Fix comment style.

* Check setup.py with flake8.

- Fix flake8 errors.

* Move function out of class scope.

* Fix function paramter list

* Fix formatting.

python/tox.ini

@@ -22,7 +22,7 @@ deps =
   flake8-bugbear
 commands=
   {envbindir}/python setup.py develop
-  flake8 {posargs:pyngraph/ ngraph/ examples/}
+  flake8 {posargs:pyngraph/ ngraph/ examples/ setup.py}
   flake8 --ignore=D100,D101,D102,D103,D104,D105,D107,W503 test/  # ignore lack of docs in tests
   mypy --config-file=tox.ini {posargs:pyngraph/ ngraph/ examples/} # Use MyPy in Python 3 only
   pytest {posargs:test/}