Closure/method definition question for Python 2.7

[Brunick, Gerard:(Constellation)]

The following code:

---
class Test(object):
    x = 10

    def __init__(self):
        self.y = x

t = Test()
---

raises

NameError: global name 'x' is not defined.

in Python 2.7.  I don't understand why.  I would assume that when __init__ is being defined, it is just a regular old function and x is a variable in an outer scope, so the function __init__ would close over the variable x.  Moreover, the variable x is not being modified, so this should be O.K.  For example, the following is fine (if nonsensical):

---
def outer():
    x = 10

    def __init__(self):
        self.y = x

    return __init__

t = outer()
print t
---

Can anyone explain this behavior?  It is clear that you could simply use self.x to access the variable x inside of __init__, but this isn't really the point of the question.  

Thanks in advance,
Gerard

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