>>> class X(object):
...   def __getattribute__(self, name):
...     if name == "__iter__":
...       import new
...       return new.instancemethod(lambda self: iter([1,2,3,4]), self, X)
...
...   def __iter__(self):
...     return iter([9,10,11,12])
...
>>> x = X()
>>> list(x)
[9, 10, 11, 12]
>>> list(x.__iter__())
[1, 2, 3, 4]