There are a ton of open source projects that have done python 2/3 simultaneously in practice. I get your point though about not being able to run full integrat

There are a ton of open source projects that have done python 2/3 simultaneously in practice. I get your point though about not being able to run full integration tests due to dependencies. Still, if you were making a good effort to keep the code Python 3 compliant, it would make upgrading much easier. Also, my other suggestion- contributing to Python 3 compatibility for modules you depend on! That will give you Python 3 experience :)