I think we can remove the `!` from this. Honestly, I don't remember why I added now, usually because a method does something dangerous, maybe to do with it explicitly raising on failure, but... that's not terribly out of the ordinary for this code. Regardless, I think `start_puppet_from_source_on` and `stop_puppet_from_source_on` should be consistent in their endings. It's a little orthogonal to the spirit of this PR, but, while were making my original code functional, lets make it more consistent as well.