Install Python 3.6 here
Error solution for 'add-repository here
In Ubuntu 16.04 default python is 2.7 and defaults python3 is 3.5. But if you want to install python 3.6 or above I found few seps you need to follow as given below.
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.5 1
sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/python3.6 2
The above command wil install an additional python to your system. Say now you will have 2.7, 3.5 and 3.6 in your /usr/bin/.
System gives you the liberty to choose which python you wanted to continue using below command:
``
sudo update-alternatives --config python3
Ater this you can check your python version using:
$ python3 -V Python 3.6.9