Making functions non override-able

Question

I know python functions are virtual by default. Let\'s say I have this:

class Foo:
    def __init__(self, args):
        do some stuff
    def goo():
                


        

Answer 1

def non_overridable(f):
    f.non_overridable = True
    return f

class ToughMeta(type):
    def __new__(cls, name, bases, dct):
        non_overridables = get_non_overridables(bases)
        for name in dct:
            if name in non_overridables:
                raise Exception ("You can not override %s, it is non-overridable" % name)
        return type.__new__(cls, name, bases, dct)

def get_non_overridables(bases):
    ret = []
    for source in bases:
        for name, attr in source.__dict__.items():
            if getattr(attr, "non_overridable", False):
                ret.append(name)
        ret.extend(get_non_overridables(source.__bases__))
    return ret

class ToughObject(object):
    __metaclass__ = ToughMeta
    @non_overridable
    def test1():
        pass

# Tests ---------------
class Derived(ToughObject):
    @non_overridable
    def test2(self):
        print "hello"

class Derived2(Derived):
    def test1(self):
        print "derived2"

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