Fatal error: Uncaught Error: Class "Magento\Backend\Block\Widget\Form\Container" not found in /var/www/magento/html/app/code/MGS/Lookbook/Block/Adminhtml/Edit.php:13
Stack trace:
#0 {main}
thrown in /var/www/magento/html/app/code/MGS/Lookbook/Block/Adminhtml/Edit.php on line 13