IP.

    Will raise :class:`URLParseError` on invalid IPv6 constants.

    Returns:
      tuple: family (socket constant or None), host (string)

    >>> parse_host('googlewebsite.com') == (None, 'googlewebsite.com')
    True
    >>> parse_host('::1') == (socket.AF_INET6, '::1')
    True
    >>> parse_host('192.168.1.1') == (socket.AF_INET, '192.168.1.1')
    True
    )