Fatal error: Uncaught TypeError: TokyoClub\Utility::convertCase(): Argument #1 ($input) must be of type string, null given, called in /home/ntakeshi/class/EventCreateControllerForOrganizers.php on line 81 and defined in /home/ntakeshi/class/Utility.php:278 Stack trace: #0 /home/ntakeshi/class/EventCreateControllerForOrganizers.php(81): TokyoClub\Utility::convertCase() #1 /home/ntakeshi/www/mypage/bookings/temporary/index.php(24): TokyoClub\EventCreateControllerForOrganizers->buildQueryParameters() #2 {main} thrown in /home/ntakeshi/class/Utility.php on line 278