ubuntu change python python from 3.9 to 3.8 code example
Example: change python 3.5 to 3.6 ubuntu
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
sudo update-alternatives --config python3