I often hear this, but I just don't see this working in practice. A very similar example I have experience with, I've often worked with people who tried to wri

I often hear this, but I just don't see this working in practice. A very similar example I have experience with, I've often worked with people who tried to write code that would be "compatible with Windows" (I primary work in a Linux environment). It makes the code more difficult to read and as soon as you try and run it in Windows it fails spectacularly. You can write code that's compatible with both Python 2 and 3, but I don't think you can expect to be using Python 2 exclusively and write code that works well in Python 3 unless you're constantly running it with Python 3. Especially, if you don't have much firsthand Python 3 experience. This is much easier if your code is isolated from those dependencies and you write tests that run in both Python 2 and 3, but that's quite a bit more of a commitment than you seem to be implying.