[luhn]

I use `pipenv install --deploy --system`. Doesn't create a virtualenv and verifies the lock file.

Of course, I definitely understand where you're coming from. It took quite a while for me to figure that out, because --deploy is not well documented.

[ben509]

I'm not sure I want to use --system in CI, just to avoid differences with development machines if possible. That does simplify baking a Docker image, though.