Tight Multiversion Python Re-development Cycle

cd \~/work/python
mkdir env3
# Create the virtual environment support
python3 -m venv env
# subdirectory bin created with all symlink'd executables (ie., pytest, python3, activate)

# Following source command CANNOT be done from a script file but only from the CURRENT shell
source bin/activate

# Now ready to add new (or existing) Python package to within Python3 environment
git clone <https://github.com/jdoe/myrepo.git>

# Go into newly created package repo
cd myrepo

# Depending if package is ready, make said package 'pseudo-installed' and live edit-able
# This enables you to skip the "install" part
# of the tight "edit python source→pip install→ pytest → edit python
source" development loop.
if \[ -r setup.py \]; then
pip install -e .
else
echo "No setup.py file found; must be a new environment or incorrect
subdirectory."
fi