We don't. To be honest, I didn't realize PyPy supported Python 3. I thought it was eternally stuck on Python 2.7.

So the good: It apparently now supports Python 3.9? Might want to update your front page, it only mentions Python 3.7.

The bad: It only supports Python 3.9, we use newer features throughout our code, so it'd be painful to even try it out.