Fatal error: Uncaught Error: Class 'Corporate_Drone' not found in /opt/www/internett/php/PHP_Book/eksempler/ch07 - Advanced OOP Features/listing7-2.php:4 Stack trace: #0 {main} thrown in /opt/www/internett/php/PHP_Book/eksempler/ch07 - Advanced OOP Features/listing7-2.php on line 4