How to use the node-opcua-address-space.Namespace function in node-opcua-address-space

//----------------------------------------------------------------------------------------------------------------------
// Server services
//----------------------------------------------------------------------------------------------------------------------
module.exports.OPCUAServer = require("node-opcua-server").OPCUAServer;
module.exports.RegisterServerMethod = require("node-opcua-server").RegisterServerMethod;

module.exports.ServerEngine = require("node-opcua-server").ServerEngine;
module.exports.MonitoredItem = require("node-opcua-server").MonitoredItem;
module.exports.ServerSession = require("node-opcua-server").ServerSession;
module.exports.Subscription = require("node-opcua-server").Subscription;
module.exports.MonitoredItem = require("node-opcua-server").MonitoredItem;

module.exports.generate_address_space = require("node-opcua-address-space").generate_address_space;
module.exports.AddressSpace = require("node-opcua-address-space").AddressSpace;
module.exports.Namespace = require("node-opcua-address-space").Namespace;

module.exports.SessionContext = require("node-opcua-address-space").SessionContext;
// basic opcua NodeClass
module.exports.UAObject = require("node-opcua-address-space").UAObject;
module.exports.UAMethod = require("node-opcua-address-space").UAMethod;
module.exports.UAVariable = require("node-opcua-address-space").UAVariable;
module.exports.UADataType = require("node-opcua-address-space").UADataType;

module.exports.getAddressSpaceFixture = require("node-opcua-address-space/test_helpers/get_address_space_fixture").getAddressSpaceFixture;
module.exports.OPCUADiscoveryServer = require("node-opcua-server-discovery").OPCUADiscoveryServer;

module.exports.basic_types = require("node-opcua-basic-types");

// version
module.exports.version = require("./package.json").version;