[Python-ideas] The prohibition overrides the class method

[Иван Спиненко]

Hello, I want to apologize for my English.
I propose to make an analogue of the final specifier in C ++. In class
abc.ABCMeta has decorator abstractmethod, you can add decorator finalmethod.

I have a sketch of implementation:
def finalmethod(funcobj):
    funcobj.__isfinalmethod__ = True
    return funcobj

class Override(ABCMeta):
    def __init__(cls, name, bases, namespace):
        super(Override, cls).__init__(name, bases, namespace)
        finals = {name
                        for name, value in namespace.items()
                        if getattr(value, "__isfinalmethod__", False)
        }

        for base in bases:
            for name in getattr(base, "__finalmethods__", set()):
                value = getattr(cls, name, None)
                if getattr(value, "__isfinalmethod__", False):
                    finals.add(name)
                else:
                    raise TypeError("function '" + str(value.__name__) + "'
in class '" + str(cls.__name__) + "' is final")
        cls.__finalmethods__ = frozenset(finals)
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