Fatal error: Uncaught Functional\Exceptions\InvalidArgumentException: Functional\flatten() expects parameter 1 to be array or instance of Traversable, integer given in /var/www/vhosts/druckerpatronenexpress.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php:272 Stack trace: #0 /var/www/vhosts/druckerpatronenexpress.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php(70): Functional\Exceptions\InvalidArgumentException::assertCollectionAlike() #1 /var/www/vhosts/druckerpatronenexpress.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Flatten.php(26): Functional\Exceptions\InvalidArgumentException::assertCollection() #2 /var/www/vhosts/druckerpatronenexpress.de/httpdocs/includes/src/Link/LinkGroup.php(136): Functional\flatten() #3 /var/www/vhosts/druckerpatronenexpress.de/httpdocs/includes/src/Link/LinkGroupList.php(200): JTL\Link\LinkGroup->map() #4 /var/www/vhosts/druckerpatronenexpress.de/httpdoc in /var/www/vhosts/druckerpatronenexpress.de/httpdocs/includes/vendor/lstrojny/functional-php/src/Functional/Exceptions/InvalidArgumentException.php on line 272