sudo apt install python3 vs sudo apt-get install python 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