Validate Python 3 compatible syntax

[ncouture]

There are at least some Python >= 3 invalid syntax used in this project (see print statements added in #130).

This suggests there is currently no such validation in place or the snippets are not validated to be compatible with Python >= 3.

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[ncouture]

As a side note since this ticket discusses syntax validation; I'm not sure what's the general rule of thumb when it comes to the Python syntax style used in their projects but as there a few inconsistencies with their style guide for instance .pylintrc defines line length to be of a maximum of 100 characters and your style guide prescribes 80 characters.

I would like to suggest using yapf. For example the following yapf configuration makes it apply many changes based on Google's Python style guide:

[style]
based_on_style = google

equivalent command that shows a diff:

$ yapf --style=google -r -d .

[hiranya911]

We test the sources on both Python 2 and 3. The snippets have been upgraded to Python 3 syntax as of #157.