Fatal error: Uncaught Error: Class "OpenSpout\Writer\AbstractWriter" not found in /srv/www/htdocs/moodle/lib/openspout/src/Writer/AbstractWriterMultiSheets.php:14 Stack trace: #0 {main} thrown in /srv/www/htdocs/moodle/lib/openspout/src/Writer/AbstractWriterMultiSheets.php on line 14