Sets Module Bug?

[Chris S.]

 >>> from sets import *
 >>> Set((1,2,3))
Set([1, 2, 3])
 >>> Set([1,2,3])
Set([1, 2, 3])
 >>> Set(([1,2,3],[4,5,6]))
Traceback (most recent call last):
   File "<input>", line 1, in ?
   File "sets.py", line 399, in __init__
     self._update(iterable)
   File "sets.py", line 344, in _update
     data[element] = value
TypeError: list objects are unhashable

How can a Set using a tuple or list be ok, but not a tuple of lists?