Add a new :class:`RTCRtpTransceiver`.

def addTransceiver(self, trackOrKind, direction='sendrecv'):
        """
        Add a new :class:`RTCRtpTransceiver`.
        """
        self.__assertNotClosed()

        # determine track or kind
        if hasattr(trackOrKind, 'kind'):
            kind = trackOrKind.kind
            track = trackOrKind
        else:
            kind = trackOrKind
            track = None
        if kind not in ['audio', 'video']:
            raise InternalError('Invalid track kind "%s"' % kind)

        # check direction
        if direction not in sdp.DIRECTIONS:
            raise InternalError('Invalid direction "%s"' % direction)

        # don't add track twice
        if track:
            self.__assertTrackHasNoSender(track)

        return self.__createTransceiver(
            direction=direction,
            kind=kind,
            sender_track=track)