python ubuntu change 3.6 to 3.9 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