Slixmpp is an MIT licensed XMPP library for Python 3.5+. It is a fork of SleekXMPP because Sleek is no longer maintained.
Slixmpp's goals is to only rewrite the core of the library (the low level socket handling, the timers, the events dispatching) in order to remove all threads.
By and large, it seems as if you could just drop this module in and it'd work. My code uses threads, so it might take a little more tinkering than that.