screen/application/common/service/UserSvc.php

<?php
namespace app\common\service;


use app\common\model\User;
use traits\think\Instance;

class UserSvc{
    use Instance;

    public static function getSellerId($user){
        if($user instanceof User){
            return $user->admin_id;
        }
        return User::where('id',$user)->value('admin_id');
    }
}