keys in dictionary

[Georges Barthelemy]

use (1,2) , (3,4)....


"Shi Mu" <samrobertsmith at gmail.com> a écrit dans le message de news: 
mailman.987.1132638229.18701.python-list at python.org...
I run the following code and got wrong message, but I still want to
make [1,2],[4,3] and [6,9]
to be keys of the dictionary or change the style a little bit. How to do 
that?
Thanks!

>>> p=[[1,2],[4,3],[6,9]]
>>> n=dict([(x,[]) for x in p])
Traceback (most recent call last):
  File "<interactive input>", line 1, in ?
TypeError: list objects are unhashable
>>>