Damn, Python is used throughout much of Ubuntu for system scripts and software,
and software relies on having Python (and the commands to start Python)
in a certain spot. do back then.
rm /usr/bin/python3
ln -s /usr/bin/python3.7 /usr/bin/python3
# create alias in ~/.bash_aliases
alias python3='/usr/bin/python3.7'
Scripts can then start with something like:
#!/usr/bin/env python3 sudo ln -s /usr/bin/python3 /usr/bin/python