As with whichever framework you choose you will have to get inside its code to understand it, adapt to it or fix it, I would advise to choose one framework that

As with whichever framework you choose you will have to get inside its code to understand it, adapt to it or fix it, I would advise to choose one framework that has code that is pleasing to read and follow very strictly conventions. Right now my box is broken so I can't check but last I have checked Django had a relatively good pylint score, while Flask had a seemingly slightly more messy code base.