Need help with simple OOP Python question

[Kristofer Tengström]

Hi, I'm having trouble creating objects that in turn can have custom
objects as variables. The code looks like this:

---------------------------------------------

class A:
    sub = dict()
    def sub_add(self, cls):
        obj = cls()
        self.sub[obj.id] = obj

class B(A):
    id = 'inst'

base = A()
base.sub_add(B)
base.sub['inst'].sub_add(B)

print # prints a blank line
print base.sub['inst']
print base.sub['inst'].sub['inst']

----------------------------------------------

Now, what I get from this is the following:
<__main__.B instance at 0x01FC20A8>
<__main__.B instance at 0x01FC20A8>
Why is this? What I want is for them to be two separate objects, but
it seems like they are the same one. I've tried very hard to get this
to work, but as I've been unsuccessful I would really appreciate some
comments on this. I'm sure it's something really easy that I just
haven't thought of.

Python version is 2.6.5 (I'm using Panda3D to create a 2½D game).