Comment by moonchild

Looks like classes can't be closures, though:

  >>> def f():
  ...     x = 5
  ...     class Blub:
  ...             def incx(self):
  ...                     x += 1
  ...             def getx(self):
  ...                     return x
  ...     return Blub()
  ... 
  >>> j = f()
  >>> j.incx()
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "<stdin>", line 5, in incx
  UnboundLocalError: local variable 'x' referenced before assignment