super and __new__ confusion
From the Python release notes on overriding the __new__ method:
__new__is a static method, not a class method. I initially thought it would have to be a class method, and that's why I added the classmethod primitive. Unfortunately, with class methods, upcalls don't work right in this case, so I had to make it a static method with an explicit class as its first argument.
Since __new__ is a static method, super(...).__new__ returns a static method. There is no binding of cls to the first argument in this case. All arguments need to be supplied explicitly.