public function add($item)
    {
        $this->validateItem($item, $this->type);

        $items = $this->items;
        $items[] = $item;

        $col = new static($this->type);
        $col->setItemsFromTrustedSource($items);

        return $col;
    }
public function add($item)
    {
        $this->validateItem($item, $this->type);

        $items = $this->items;
        $items[] = $item;

        $col = new static($this->type);
        $col->setItemsFromTrustedSource($items);

        return $col;
    }
{@inheritdoc}