Illuminate\Support\Collection::getArrayableItems PHP Method

    protected function getArrayableItems($items)
    {
        if (is_array($items)) {
            return $items;
        } elseif ($items instanceof self) {
            return $items->all();
        } elseif ($items instanceof Arrayable) {
            return $items->toArray();
        } elseif ($items instanceof Jsonable) {
            return json_decode($items->toJson(), true);
        } elseif ($items instanceof JsonSerializable) {
            return $items->jsonSerialize();
        } elseif ($items instanceof Traversable) {
            return iterator_to_array($items);
        }
        return (array) $items;
    }

 protected function getArrayableItems($items)
 {
     $items = parent::getArrayableItems($items);
     $items = array_map([$this, 'validateItem'], $items);
     return $items;
 }