sorting a list

[ketulp_baroda at yahoo.com]

Hi
I want to sort a list.
My problem is:

>>> a=['a','f','F','A','D']
>>> a.sort()
>>> a
['A','D', 'F', 'a', 'f']


But I am actually looking for an output:
['A','a','D','F','f']

Is there any module to sort a list this way?