gistfile1.txt

Python 2.7.1 (r271:86832, Jun 16 2011, 16:59:05) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> a=()
>>> a+=(2,)
>>> print(a)
(2,)
>>> 

Python 3.2.2 (default, Apr  5 2012, 18:13:42) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> a=()
>>> a+=(12,)
>>> print(a)
(12,)
>>> a+=(24,)
>>> print(a)
(12, 24)
>>>