How to use the @theia/application-manager.ApplicationPackageManager function in @theia/application-manager

(function (): void {
    const projectPath = process.cwd();
    const appTarget: ApplicationProps.Target = yargs.argv['app-target'];
    const manager = new ApplicationPackageManager({ projectPath, appTarget });
    const target = manager.pck.target;

    yargs
        .command({
            command: 'start',
            describe: 'start the ' + manager.pck.target + ' backend',
            handler: async () => {
                try {
                    await manager.start(commandArgs('start'));
                } catch (err) {
                    console.error(err);
                    process.exit(1);
                }
            }
        })
        .command({

createPackageManager(): ApplicationPackageManager {
        return new ApplicationPackageManager(Object.assign({
            log: this.logger.info.bind(this.logger),
            error: this.logger.error.bind(this.logger),
            registry: this.registry
        }, this.options));
    }