产品批量上传页面出现 500 错误

PHP 版本： PHP 7.4.3
说明：在 php7.1.x 版本中不存在此问题。

错误提示：

Http status: 500 error
ajaxOptions: error
thrownError:
PHP Deprecated Warning 'yii\base\ErrorException' with message 'Cannot use "parent" when current class scope has no parent' 

in fecmall/vendor/fancyecommerce/fecshop/app/appadmin/modules/Catalog/block/productupload/Manager.php:34

Stack trace:
#0 fecmall/vendor/yiisoft/yii2/BaseYii.php(293): yii\base\ErrorHandler->handleError()
#1 fecmall/vendor/yiisoft/yii2/BaseYii.php(293): include()
#2 [internal function]: yii\BaseYii::autoload()
#3 fecmall/vendor/fancyecommerce/fecshop/app/appadmin/modules/AppadminController.php(167): spl_autoload_call()
#4 fecmall/vendor/fancyecommerce/fecshop/app/appadmin/modules/Catalog/controllers/ProductuploadController.php(24): fecshop\app\appadmin\modules\AppadminController->getBlock()
#5 [internal function]: fecshop\app\appadmin\modules\Catalog\controllers\ProductuploadController->actionManager()
#6 fecmall/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array()
#7 fecmall/vendor/yiisoft/yii2/base/Controller.php(157): yii\base\InlineAction->runWithParams()
#8 fecmall/vendor/yiisoft/yii2/base/Module.php(528): yii\base\Controller->runAction()
#9 fecmall/vendor/yiisoft/yii2/web/Application.php(103): yii\base\Module->runAction()
#10 fecmall/vendor/yiisoft/yii2/base/Application.php(386): yii\web\Application->handleRequest()
#11 fecmall/appadmin/web/index.php(50): yii\base\Application->run()
#12 {main}

错误位置：

fecmall/vendor/fancyecommerce/fecshop/app/appadmin/modules/Catalog/block/productupload/Manager.php

    public function init()
    {
        parent::init();
    }