ubuntu@jr-x6:~/nova$ apt policy python-rfc3986
python-rfc3986:
  Installed: 0.2.0-2
  Candidate: 0.2.0-2
  Version table:
 *** 0.2.0-2 500
        500 http://hamburg_zone02.clouds.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
        100 /var/lib/dpkg/status
ubuntu@jr-x6:~/nova$ python
Python 2.7.12 (default, Jul  1 2016, 15:12:24) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import rfc3986
>>> url="https://x.y:55/"
>>> rfc3986.is_valid_uri(url, require_scheme=True, require_authority=True)
True
>>> url="https://x.y-z:55/"
>>> rfc3986.is_valid_uri(url, require_scheme=True, require_authority=True)
False
>>>