How to use the node-opcua-service-endpoints.UserTokenPolicy function in node-opcua-service-endpoints

// services
module.exports.browse_service = require("node-opcua-service-browse");
module.exports.read_service = require("node-opcua-service-read");
module.exports.write_service = require("node-opcua-service-write");
module.exports.call_service = require("node-opcua-service-call");

module.exports.session_service = require("node-opcua-service-session");
module.exports.AnonymousIdentityToken = module.exports.session_service.AnonymousIdentityToken;
module.exports.UserNameIdentityToken = module.exports.session_service.UserNameIdentityToken;

module.exports.register_node_service = require("node-opcua-service-register-node");

module.exports.get_endpoints_service = require("node-opcua-service-endpoints");
module.exports.EndpointDescription = require("node-opcua-service-endpoints").EndpointDescription;
module.exports.ApplicationType = require("node-opcua-service-endpoints").ApplicationType;
module.exports.UserTokenPolicy = require("node-opcua-service-endpoints").UserTokenPolicy;
module.exports.UserIdentityTokenType = require("node-opcua-service-endpoints").UserIdentityTokenType;

module.exports.subscription_service = require("node-opcua-service-subscription");
module.exports.historizing_service = require("node-opcua-service-history");
module.exports.discovery_service = require("node-opcua-service-discovery");
module.exports.secure_channel_service = require("node-opcua-service-secure-channel");

module.exports.translate_browse_paths_to_node_ids_service = require("node-opcua-service-translate-browse-path");
module.exports.BrowsePath = require("node-opcua-service-translate-browse-path").BrowsePath;
module.exports.makeRelativePath = require("node-opcua-service-translate-browse-path").makeRelativePath;
module.exports.makeBrowsePath = require("node-opcua-service-translate-browse-path").makeBrowsePath;

module.exports.query_service = require("node-opcua-service-query");
module.exports.node_managment_service = require("node-opcua-service-node-management");

module.exports.ServerState = require("node-opcua-common").ServerState;