How to use the @vendure/core/dist/bootstrap.preBootstrapConfig function in @vendure/core

export async function clearAllTables(config: VendureConfig, logging = true) {
    config = await preBootstrapConfig(config);
    const entityIdStrategy = config.entityIdStrategy;
    const connection = await createConnection({ ...config.dbConnectionOptions });
    if (logging) {
        console.log('Clearing all tables...');
    }
    try {
        await connection.synchronize(true);
    } catch (err) {
        console.error('Error occurred when attempting to clear tables!');
        console.error(err);
    } finally {
        await connection.close();
    }
    if (logging) {
        console.log('Done!');
    }

private async bootstrapForTesting(
        userConfig: Partial,
    ): Promise<[INestApplication, INestMicroservice | undefined]> {
        const config = await preBootstrapConfig(userConfig);
        Logger.useLogger(config.logger);
        const appModule = await import('@vendure/core/dist/app.module');
        try {
            DefaultLogger.hideNestBoostrapLogs();
            const app = await NestFactory.create(appModule.AppModule, { cors: config.cors, logger: false });
            let worker: INestMicroservice | undefined;
            await app.listen(config.port);
            if (config.workerOptions.runInMainProcess) {
                const workerModule = await import('@vendure/core/dist/worker/worker.module');
                worker = await NestFactory.createMicroservice(workerModule.WorkerModule, {
                    transport: config.workerOptions.transport,
                    logger: new Logger(),
                    options: config.workerOptions.options,
                });
                await worker.listenAsync();
            }