def __init__(self, host=None, port=PORT):
        """
        Create new instance.

        @param host: our hostname/IP as set in Via headers.
        @param port: our port as set in Via headers.
        """
        self.host = host or socket.getfqdn()
        self.port = port
        Base.__init__(self)

        Create new instance.

        @param host: our hostname/IP as set in Via headers.
        @param port: our port as set in Via headers.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/sip.py