def commissionerUnregister(self):
        """stop commissioner

        Returns:
            True: successful to stop commissioner
            False: fail to stop commissioner
        """
        print '%s call commissionerUnregister' % self.port
        cmd = WPANCTL_CMD + 'commissioner stop'
        print cmd
        if self.__sendCommand(cmd)[0] != 'Fail':
            self.isActiveCommissioner = False
            return True
        else:
            return False