In addition, Fabric doesn't support Python 3. The feedback I've gotten back on when Python 3 will be supported and how much of the legacy fabric API's will be supported is even more limited.
There is a fork with Python 3 support: https://github.com/mathiasertl/fabric/
If you use fabtools, I maintain a fork of it for fabric3: https://github.com/develtech/fabtools/tree/fabric3