Convert from numbers to letters

[rh0dium]

Python 2.3.5 (#1, Mar 20 2005, 20:38:20)
[GCC 3.3 20030304 (Apple Computer, Inc. build 1809)] on darwin

Traceback (most recent call last):
  File "<stdin>", line 1, in ?
NameError: name 'sorted' is not defined

I think you're probably using 2.4 ??