myclassmethod.py

import new


class myclassmethod(object):
    def __init__(self, func):
        self.func = func
        self._first = True

    def __get__(self, instance, klass):
        if self._first:
            self.func = new.instancemethod(self.func, klass, type)
            self._first = False
        return self.func


class Foo(object):
    value = 0

    @classmethod
    def foo(cls):
        cls.value += 1
        return cls.value

    @myclassmethod
    def bar(cls):
        cls.value += 1
        return cls.value


if __name__ == '__main__':
    print dir(Foo.foo) == dir(Foo.bar)
    print Foo.foo
    print Foo().foo
    print Foo.bar
    print Foo().bar
    print Foo.foo()
    print Foo().foo()
    print Foo.bar()
    print Foo().bar()