Übungsleiter

Fatal error: Uncaught TypeError: implode(): Argument #2 ($array) must be of type ?array, string given in /homepages/9/d267584169/htdocs/uebungsleiter.php:86 Stack trace: #0 /homepages/9/d267584169/htdocs/uebungsleiter.php(86): implode(Array, ', ') #1 {main} thrown in /homepages/9/d267584169/htdocs/uebungsleiter.php on line 86