How to use the kervi.utility.nethelper.get_free_port function in kervi

"port": nethelper.get_free_port([9434, 9435, 9436])
        },
        "log" : {
            "levels":["fatal", "error", "warning", "information", "debug"],
            "level":"verbose",
            "console_level":"verbose",
            "file": "kervi.log",
            "max_file_size": 1000000,
            "resetLog": False
        },
        "modules":[],
        "network" : {
            "ip": nethelper.get_ip_address(),
            "http_port": nethelper.get_free_port([80, 8080, 8000]),
            "ws_port": nethelper.get_free_port([9000, 9001, 9002]),
            "ipc_root_port": nethelper.get_free_port([9500]),
            "ipc_root_address": nethelper.get_ip_address()
        },
        "plugin_manager":{
            "plugin_types":{
                "default": {
                    "managed": False,
                    "own_process": True
                },
                "messaging": {
                    "own_process": False,
                    "managed": True  
                },
                "ui": {
                    "own_process": True,
                    "managed": False
                },

try:
            from kervi.version import VERSION
        except:
            VERSION="0.0.0"

        self._logger.verbose("kervi version: %s", VERSION)

        import kervi.hal as hal
        hal_driver = hal._load(self.config.platform.driver)
        if hal_driver:
            self._logger.verbose("platform driver: %s", hal_driver)
            self._logger.verbose("board: %s", hal.get_board_name())
            
        from kervi.plugin.message_bus.bus_manager import BusManager
        self.bus_manager = BusManager(self._log_queue)
        self.config.network.ipc_root_port = nethelper.get_free_port([self.config.network.ipc_root_port])
        self.bus_manager.load("kervi-main", self.config.network.ipc_root_port, None, self.config.network.ipc_root_address)
        
        from kervi import spine
        self.spine = spine.Spine()
        self.spine.register_query_handler("GetApplicationInfo", self._get_application_info)
        self.spine.register_query_handler("getProcessInfo", self.get_process_info)
        self.spine.register_event_handler("modulePing", self._module_ping)
        self.spine.register_event_handler("processReady", self._process_ready, scope="app-" + self.config.application.id)
        self.spine.register_event_handler("WebAppReady", self._webapp_ready, scope="app-" + self.config.application.id)
        self.spine.register_event_handler("websocketReady", self._websocket_ready, scope="app-" + self.config.application.id)
        self._module_processes = []
        self._process_info = []
        self._process_info_lock = threading.Lock()

        self._kervi_modules = []
        self._kervi_modules_lock = threading.Lock()

self.spine.send_command("startThreads", local_only=True)
        time.sleep(.5)
        module_port = self.config.network.ipc_root_port

        self._process_info_lock.acquire()
        self._process_info = [{"id":"IPC", "ready":False}]
        self._process_info_lock.release()

        module_port += 1
        self._module_processes += [
            process._start_process(
                "app-" + self.config.application.id,
                "IPC",
                self.config,
                nethelper.get_free_port([module_port]),
                app_helpers._KerviSocketIPC
            )
        ]

        for module in self.config.modules:
            self._process_info_lock.acquire()
            self._process_info += [{"id":module, "ready":False}]
            self._process_info_lock.release()

            module_port += 1
            self._module_processes += [
                process._start_process(
                    "app-" + self.config.application.id,
                    module,
                    self.config,
                    nethelper.get_free_port([module_port]),