I'm a Python avoider, on macOS. I have python3 installed via homebrew. Running

./run_tests.py -c gfortran -C gcc

gives

env: python: No such file or directory

Brew doesn't seem to install a python, just a python3.

What's the canonical way that Python programmers specify which python to resolve to?

/usr/bin/env python3?

Or coerce the homebrew install to make me a link from python to python3?

Or create it manually? (Ick.)