Fatal error: Uncaught TypeError: array_keys(): Argument #1 ($array) must be of type array, null given in /home/clickboo/public_html/lernkaertchen.ch/lib/src/Model/Karten.php:232
Stack trace:
#0 /home/clickboo/public_html/lernkaertchen.ch/lib/src/Model/Karten.php(232): array_keys(NULL)
#1 /home/clickboo/public_html/lernkaertchen.ch/lib/src/Controller/Frontend.php(414): Aisberg\Model\Karten::filterGelernteKarten(Array, NULL)
#2 /home/clickboo/public_html/lernkaertchen.ch/lib/src/Bootstrap.php(245): Aisberg\Controller\Frontend->indexAction(Array)
#3 /home/clickboo/public_html/lernkaertchen.ch/index.php(14): Aisberg\Bootstrap->run()
#4 {main}
thrown in /home/clickboo/public_html/lernkaertchen.ch/lib/src/Model/Karten.php on line 232