"ajikoe at gmail.com" wrote:
> when you use a = a + 'world' python sees it as an error because of
> different type.
>
> But when you use a += 'world'
> python will change the right into list (because a is a list).
"changing into a list" is a bit misleadning; to bit a bit more precise,
you may want to change that to
python will treat the right as a sequence
</F>