ubuntu20 install python3.7

The default python version of ubuntu20 is python3.8.

----------------------------Install python3.7 version--------------
Development requires python3.7
installation method:
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt-get update
sudo apt-get install python3.7

confirm:

$ > whereis python

Should key see python3.7

-------------------------------------------------many Version management------------------------------------

//Python multi-version switching

update-alternatives  --list  <NAME>

update-alternatives --install //Add various versions of python //Parameter name = python

update-alternatives --set //Set the current version