Porting over code to python3 from python2 be like:
(Cakechat, in this case)

Day 0 of n of python 3 compatibility work:
This should be _easy_, just use six and do magic!

Day 1 of n:
Oh, true division is default instead of integer division, so I need to replace `/` with `//` in a few places.

Day 2 of n:
Oh, map in python2 behaves differently than map in python3, one returns a list, other an iterator. Time to replace it with `list(map())` then.

Day 3 of n:
Argh, lambdas don't evaluate automatically, time to fix that too.

Day 4 of n:
Why did I bother trying to port this code in the first place? It's been so long and I DON'T EVEN KNOW WHAT IS BROKEN BECAUSE THE STUFF RUNS WHEN I BREAKPOINT AND STEP THROUGH BUT NOT WHEN I RUN IT DIRECTLY?!

Day ??? of n:
[predicted]
*gives up*
I've had enough.

!rant

That level of satisfaction when you successfully port a Python2 Project to Python3 and implement proper backward-compatibility - without 2to3!

Flask people
so I was given this old flask project, around 3k lines written in py2, the code is simply old and not refactored. So, it's pile of shit. Migrations completely botched as the original author created reference to live data in models.
Very strict line formatting resulting in backslashed ternary conditions.
Even saw manually formatted json responses... _line by line_.

My job is to clean this mess and eventually do as much as possible to freshen the whole project.
Currently just refucktoring the code as it's the only easy thing to do out of everything that could be done (it's still slow process).

Any tricks and tips? currently considering to try upgrading it to py3 but it feels like throwing gunpowder into already burning house.

Python needs a tool called 2to23.

Also, 2to3 does NOT take into account things like byte encoding changes. Kind of annoying.