No trees in the stdlib?

[MRAB]

Lawrence D'Oliveiro wrote:
> In message <mailman.2140.1245996088.8015.python-list at python.org>, João 
> Valverde wrote:
> 
>> Simple example usage case: Insert string into data structure in sorted
>> order if it doesn't exist, else retrieve it.
> 
>     the_set = set( ... )
> 
>     if str in the_set :
>         ... "retrieval" case ...
>     else :
>         the_set.add(str)
>     #end if
> 
> Want sorted order?
> 
>     sorted(tuple(the_set))
> 
> What could be simpler?
> 
Why not just "sorted(the_set)"?