Fatal error: Uncaught Error: Class 'InventoryCore' not found in /home/koontak127/public_html/php/sale.php:10 Stack trace: #0 /home/koontak127/public_html/php/sale.php(65): Sale->__construct() #1 /home/koontak127/public_html/php/sale.php(454): OnlineSale->__construct() #2 /home/koontak127/public_html/php/office-utils.php(2357): ShopSale->__construct() #3 {main} thrown in /home/koontak127/public_html/php/sale.php on line 10