code: public function findLastIndex(callable $condition)
      {
          $index = -1;
  
          for ($i = count($this->items) - 1; $i >= 0; $i--) {
              if ($condition($this->items[$i])) {
                  $index = $i;
                  break;
              }
          }
  
          return $index;
      }
docs: {@inheritdoc}