class A:
    def __init__(self, a):
        self.a = a
    def printa(self):
        print(self.a)
    def test2(self, _):
        print(34)

    def test3(self):
        print(5)

class B(A):
    def test(self, fun):
        fun(self)
    def test3(self, a):
        super().test3()
        print(a)

class C:
    def __init__(self):
        self.foo()
    def foo(self):
        self.a = 10