Stops a packet capture.

        :param slot_number: slot number
        :param port_number: port number

def stop_capture(self, slot_number, port_number):
        """
        Stops a packet capture.

        :param slot_number: slot number
        :param port_number: port number
        """

        try:
            adapter = self._slots[slot_number]
        except IndexError:
            raise DynamipsError('Slot {slot_number} does not exist on router "{name}"'.format(name=self._name,
                                                                                              slot_number=slot_number))
        if not adapter.port_exists(port_number):
            raise DynamipsError("Port {port_number} does not exist in adapter {adapter}".format(adapter=adapter,
                                                                                                port_number=port_number))

        nio = adapter.get_nio(port_number)

        if not nio:
            raise DynamipsError("Port {slot_number}/{port_number} is not connected".format(slot_number=slot_number,
                                                                                           port_number=port_number))

        yield from nio.unbind_filter("both")

        log.info('Router "{name}" [{id}]: stopping packet capture on port {slot_number}/{port_number}'.format(name=self._name,
                                                                                                              id=self._id,
                                                                                                              nio_name=nio.name,
                                                                                                              slot_number=slot_number,
                                                                                                              port_number=port_number))