It was a primary purpose of `secrets` to be a place where security best practices could be implemented, and changed over time, with no concern about backward compatibility for people who don't use it.

So if `secrets` needs to supply a class with all the methods of random.Random, it should derive its own subclass (or derive from random.SystemRandom, and override the only two methods that explicitly invoke _urandom() - everything else ends up using .random() or .getrandbits()).