By convention, the first argument in a class method, i.e. methods decorated with @classmethod, is named cls as a
representation and a reminder that the argument is the class itself. If you were to name the argument something else, you would stand a good chance of
confusing both users and maintainers of the code. It might also indicate that the cls parameter was forgotten, in which case calling the
method will most probably fail. This rule also applies to methods __init_subclass__, __class_getitem__ and
__new__ as their first argument is always the class instead of "self".
By default this rule accepts cls and mcs, which is sometime used in metaclasses, as valid names for class parameters. You
can set your own list of accepted names via the parameter classParameterNames.
