book_admin/application/common/internalInterface/SingletonService.php

<?php
/**
 * Created by PhpStorm.
 * User: Bear
 * Date: 2018/11/9
 * Time: 上午10:28
 */

namespace app\common\internalInterface;

/**
 * 单例接口文件
 * Interface BaseService
 * @package cps\src\Service
 */
interface SingletonService
{
    /**
     * @return $this
     */
    public static function instance();
}