Binary search tree

[maxim.novak at gmail.com]

Hi,

I have to get list of URLs one by one and to find the URLs that I have
more than one time(can't be more than twice).

I thought to put them into binary search tree, this way they'll be
sorted and I'll be able to check if the URL already exist.

Couldn't find any python library that implements trees.
Is there some library of this kind in python? Or can I find it
somewhere else?