def _setrport(self, newRPort):
        """
        L{Base._fixupNAT} sets C{rport} directly, so this method sets
        C{rportValue} based on that.

        @param newRPort: The new rport value.
        @type newRPort: C{int}
        """
        self.rportValue = newRPort
        self.rportRequested = False

        L{Base._fixupNAT} sets C{rport} directly, so this method sets
        C{rportValue} based on that.

        @param newRPort: The new rport value.
        @type newRPort: C{int}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/sip.py