Fatal error: Uncaught Error: Class 'Magento\Backend\Block\Widget' not found in /home/esecureh/public_html/magdemo/vendor/magento/module-configurable-product/Block/Adminhtml/Product/Edit/Tab/Variations/Config.php:16 Stack trace: #0 {main} thrown in /home/esecureh/public_html/magdemo/vendor/magento/module-configurable-product/Block/Adminhtml/Product/Edit/Tab/Variations/Config.php on line 16