Actually, I tried that the other day. It complains about having the wrong Python, but will auto-select a version compatible with your project and run fine. For me, it selected Python 3.7 because that's what the pyproject.toml specified, even though I was running it under Python 2.
Well, except one thing: If I do `poetry update <somepackage>`, it starts upgrading other packages as well. I'm not sure what that's about...