@emrebeyler thank you for looking at my code so closely. You have brought up some interesting concerns so let me address them.

The reason I am using the naming "account1" and "account2" is because they are both authors and they are both voters, but account1 is always the inviter, and account2 is always the invitee. I use post1/post2 and vote1/vote2 naming conventions in the same way so that I always know who's inviter and who's invitee. Looking at this function now I suppose it could be renamed author/voter.

The input issues only affected the front-end. Please see sec.py for back-end filtering.

As for using a list comprehension, I'd have to look at that more closely to see how it affects logic since I'm not really used to doing it this way. I'm sure it's more pythonic, but how does it handle an empty vote list (hence why I had len(votes) > 0)? I'll play around with it. Thanks for the advice.