preCICE offers language bindings for Python. However, we only officially support Python3. This means that our tests and tutorials are only using Python3 and we cannot really promise that everything will work out of the box if you use Python2.
Therefore, I would recommend you to use Python3, if possible. However, if you code setup requires Python2, you can also try using Python2 with preCICE: The python bindings have been successfully used with Python2 some time ago and it worked. You might face some issues. But then you can, of course, open an issue on github or ask for help on gitter and we will try to get it working.