def _set_destination(self, dest):
        """_set_destination(dest: Port) -> None
         Sets this connection destination port. Do not use this
        function, use destination property instead: c.destination = dest

        """
        try:
            port = self.db_get_port_by_type('destination')
            self.db_delete_port(port)
        except KeyError:
            pass
        if dest is not None:
            self.db_add_port(dest)