pyfinal

pyfinal.py

import six

def final(f):
    f.__is_final = True
    return f

class enable_final(type):
    def __new__(cls, name, bases, d):
        for k in d:
            for base in bases:
                f = getattr(base, k, None)  # base method
                if getattr(f, '__is_final', False):
                    raise TypeError('method {} is final'.format(k))
        return type.__new__(cls, name, bases, d)

class A(six.with_metaclass(enable_final)):
    @final
    def foo(self): pass

    def bar(self): pass

class B(A):
    def bar(self): pass  # ok

class C(A):
    def foo(self): pass  # ng