Ubuntu 14.04 (Trusty) and 16.04 (Xenial)
$ sudo add-apt-repository -y ppa:jblgf0/python
$ sudo apt-get update
$ sudo apt-get install python3.6
Ubuntu 16.10 and 17.04
$ sudo apt-get update
$ sudo apt-get install python3.6
After installation for Ubuntu 14.04, 16.04, 16.10 and 17.04
To invoke the Python 3.6 interpreter, run python3.6.