Fatal error: Uncaught Error: Interface 'PHPExcel_IComparable' not found in /var/www/testing/PHPExcel_1.7.8/Classes/PHPExcel/Style/Alignment.php:36 Stack trace: #0 {main} thrown in /var/www/testing/PHPExcel_1.7.8/Classes/PHPExcel/Style/Alignment.php on line 36