Rick Harris

@snordhausen Sounds like a good idea. I wonder if the `warning` module should be used to let Mac users know that their IPv6 addresses may not be RFC compliant.

I don't think I wrote that bit of code, but I believe the idea here was that manually set environment variables should take precedence over variables specified in a file....

Thinking a bit more about this. Seems like the name `refresh=True` isn't really that descriptive of the general case; for example makes less sense if you're just running this once....

Looks useful. Think an additional function for this is probably overkill, just adding a `list` of paths we've traversed to `read_envfile` should be good enough.