URLs Not Escaped Correctly

When I use:
url = "https://www.example.com/site/Fixed%20url/"
transport = WindowsHttpAuthenticated(username=username,
                                     password=password,
                                     timeout=timeout)
Client(url, transport=transport) 

The URL becomes unescaped (has spaces instead of %20). This fix works as a temporary fix, but whatever is decoding the URL should probably be prevented from running.