No trees in the stdlib?

[Lawrence D'Oliveiro]

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?