Warning: Undefined array key "id" in /mnt/sda1/codes/tree/test.php on line 38

Fatal error: Uncaught TypeError: findParentIds(): Return value must be of type array, none returned in /mnt/sda1/codes/tree/test.php:37 Stack trace: #0 /mnt/sda1/codes/tree/test.php(39): findParentIds(Array, NULL) #1 {main} thrown in /mnt/sda1/codes/tree/test.php on line 37