where are isinstance types documented?

[Duncan Booth]

Fredrik Lundh <fredrik at pythonware.com> wrote:

> Sequences:
>      str
>      unicode
>      tuple
>      list

It is also worth mentioning that you can use "isinstance(a, basestring)" as 
a way to check for either string type although, of course, "isinstance(a, 
(str, unicode))" also works.

So far as I know there is no practical use for basestring other than using 
it in isinstance.