nonlocal

gistfile1.txt

>>> def foo():
...    a = 2
...    def bar():
...       print a
...    return bar
...
>>> foo().func_closure
(<cell at 0x02515FF0: int object at 0x023AA6CC>,)
>>> foo().func_closure[0]
<cell at 0x02589ED0: int object at 0x023AA6CC>
>>> type(foo().func_closure[0])
<type 'cell'>
>>> b = foo()
>>> b()
2
>>> import ctypes
>>> ctypes.pythonapi
>>> ctypes.pythonapi.PyCell_Set(id(b.func_closure[0]), id(3))
0
>>> b()
3