src/Model/Request/Item/ReceiptRequestItem.php
public function addItem(ItemsReceiptRequestItem $item)
    {
        if (!in_array($item, $this->items)) {
            $this->items[] = $item;
        }

        return $this;
    }
public function addItem(ItemsReceiptRequestItem $item)
    {
        if (!in_array($item, $this->items)) {
            $this->items[] = $item;
        }

        return $this;
    }
@param ItemsReceiptRequestItem $item

@return $this