It is NOT a different language. It&#x27;s not backwards compatible, sure, but usually, only minor changes are required and 2to3 helps a lot. At this point, pretty much all of the libraries are ported and their API stays the same. The libraries which haven&#x27;t been ported yet are either notable exceptions (Twisted!) or are unmaintained.<p>Very helpful for porting: <a href="http:&#x2F;&#x2F;python-future.org" rel="nofollow">http:&#x2F;&#x2F;python-future.org</a>