Why return None?

[Martin DeMello]

Ayose <ayose.cazorla at hispalinux.es> wrote:
> 
> If you can use python 2.3 or newer, try with [::-1]
> 
>     >>> def f(m, n):
>     ...     print (m + n)[::-1]
>     ... 
>     >>> f([1,2,3], [10,20,30])
>     [30, 20, 10, 3, 2, 1]

Thanks! Where can I look this up?

martin