>>> d = {'a':1,'b':(1,2,3)}
>>> d['b']
(1, 2, 3)
>>> d = {'a':1,(1,2,3):2}
>>> d[(1,2,3)]
2
>>> s = set([1,2,(1,2,3)])
>>> s
{1, 2, (1, 2, 3)}
>>> d = {'a':1,'b':(1,[2,3])}
>>> d['b']
(1, [2, 3])
>>> d = {'a':1,(1,[2,3]):2}
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'
>>> s = set([1,2,(1,[2,3])])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'