re installing python2.7 in ubuntu 20.04 code example

Example 1: install python3.7 ubuntu 20.04

sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt-get update
sudo apt-get install python3.7

Example 2: how to install python 3 on ubuntu 20.04

sudo apt install build-essential libssl-dev libffi-dev python3-dev