Python 2 is no longer a part of the default installation of Ubuntu 16.04.
As a result when you try to use the apt_get module you get the following error
error: unsupported package module wrapper API version: -1
error: Can not set up wrapper for module: apt_get
running it by hand gives you
-su: /var/cfengine/modules/packages/apt_get: /usr/bin/python: bad interpreter: No such file or directory
which leads you to this
ubuntu@ubuntu-xenial:~# python -v
The program 'python' can be found in the following packages:
I did run a quick test and switching the shebang to python3 seemed to work.
My work around at the moment is to use the old package method to install python2.