code: public function sortWith(callable $comparator, $preserveKeys = false)
      {
          $items = $this->items;
  
          $preserveKeys ? uasort($items, $comparator) : usort($items, $comparator);
  
          return $this->createFrom($items);
      }
docs: Returns a bag with the values sorted with the `$comparator`.
  
  @param callable $comparator   Function given `($itemA, $itemB)`
  @param bool     $preserveKeys Whether to preserve keys for maps or to re-index for lists
  
  @return static