classonly decorator

from functools import wraps


class classonly:
    def __init__(self, func):
        self.func = func
    def __get__(self, obj, klass=None):
        if obj is not None:
            raise TypeError("This method cannot be called from a class instance.")
        @wraps(self.func)
        def wrapper(*args):
            return self.func(klass, *args)
        return wrapper