It is pretty obvious there is a problem when your quick and easy cheat sheet is a 33 page tomb. If only Guido and company would acknowledge the problem and fix it instead of putting their fingers in their ears pretending Python 2 will cease to exist in 2020.
They acknowledge the problem, and their solution is to stop actively aiding and abetting the people who are continuing to make it worse by writing python 2 code.
Wow, what a simplification.
What about us who have and want to use massive libraries of existing Python 2 code?
"Just upgrade your libraries!" is not realistic for everyone, especially those who have to justify a mostly idealogical conversion to a similar language, and spend real time and money, outside of actually developing the end product, to do it.
Four more years of official support is a long time.
Once you decide not to support Python2 anymore, just drop the imports. They also have a Py2/3 compat cheet sheet : http://python-future.org/compatible_idioms.pdf