python 3.6 on ubuntu 16.04 code example
Example 1: ubuntu install python
# first do:
sudo apt-get update
# after do:
sudo apt-get install python3.6
# then it should be installed
Example 2: install python3.7 ubuntu 20.04
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt-get update
sudo apt-get install python3.7