(PHP 5 >= 5.2.0, PHP 7, PHP 8)
ArrayIterator::uksort — Sort by keys using a user-defined comparison function
This method sorts the elements by keys using a user-supplied comparison function.
Note: If two members compare as equal, they retain their original order. Prior to PHP 8.0.0, their relative order in the sorted array was undefined.
callback
Always returns true.