Instance of inherited nested class in outer class not allowed?

[mrstephengross]

I've got an interesting problem with my class hierarchy. I have an
outer class, in which two nested classes are defined:

class Outer:
  class Parent:
    def __init__ (self):
      print "parent!"
  class Child(Parent):
    def __init__ (self):
      Outer.Parent.__init__(self)
  foo = Child()

Note that the second nested class (Outer.Child) inherits from the
first nested class (Outer.Parent). When I run the above code, python
reports a name error:

Traceback (most recent call last):
  File "./temp.py", line 3, in ?
    class Outer:
  File "./temp.py", line 13, in Outer
    foo = Child()
  File "./temp.py", line 11, in __init__
    Outer.Parent.__init__(self)
NameError: global name 'Outer' is not defined

Apparently, python doesn't like having an instance of a derived nested
class present in the outer class. Interestingly enough, if I change
the foo variable to an instance of the parent class:

  foo = Parent()

everything is hunky-dory. Is there some syntax rule I'm breaking here?

Thanks!
--Steve