If I have:

```
class A():
    def f(self):
        print("running function, f from class A")
class B(A):
    def __init__(self):
        A.__init__(self)
    def f(self):
        print("running function, f from class B")

```

and I make an instance of class B and call f on it, we all know we'll see the message about "from class B." But is there a way for me to inspect my object and make sure my sub-class has overridden my method? Something like:

```
obj = B()
assert(not obj.f.livesIn(A))

```