Silvercart installation issue

Hello all,

I have faced the issue during silvercart shop installation, based on the document step 9(GitHub - silvercart/silvercart: SilverCart E-Commerce module for SilverStripe CMS Framework).

PHP Fatal error: Declaration of SilverCart\Admin\Controllers\ModelAdmin::getGridField($form) must be compatible with SilverStripe\Admin\ModelAdmin::getGridField(): SilverStripe\Forms\GridField\GridField in /var/www/silvercart-demo/vendor/silvercart/silvercart/src/Admin/Controllers/ModelAdmin.php on line 247

Could you please can anyone help me to resolve this issue.

Thanks in advance.