In fairness to Nick, he is not talking about the real world. Nick is talking about the hot-house environment of *education*, where fragile newbies are generally protected from real world issues.
Sure, but PEP8 is about the real world. Which is why I suggested that Nick might want to create a linter config (or whole new style guide) for his students. However, in my teaching, I always try to remember that my goal is not to have the students be successful in my class. But rather for them to learn what they need to know to use Python in the “real world” So if learning the “is None” idiom presents a stumbling block early on, but provides an opportunity to learn something that WILL matter in the real world, then that's a good thing. (I actually have a whole (small) lecture on "is" vs "==" as part of my curriculum) -CHB