There are exceptions being raised in many applications (as reported here and in http://bugs.python.org/issue25641) and there are three paths to follow: 

1. We handle this exception somewhere;
2. We avoid raising it;
3. Just leave it. I don't care about this exception.

If we chose to handle this exception we need to decide where we'll do it. At os.py module? At urllib/request.py? At all http client libraries (eg. python-requests)? At our applications?

If we chose to avoid this exception we, probably, need to implement some kind of lock/mutex in os.environ.

I can implement any of these options. You just need to decide which one is best.

If we chose the third option, we can just close this issue.