src/ClearSaleID/Entity/Request/Order.php
public function setQuantityItems( $quantityItems )
    {
        if (preg_match( '/^\d+$/', $quantityItems ) !== 1) {
            throw new InvalidArgumentException( sprintf( 'Items quantity should be a non-negative integer (%s)',
                $quantityItems ) );
        }

        $this->quantityItems = intval( $quantityItems );

        return $this;
    }
public function setQuantityItems( $quantityItems )
    {
        if (preg_match( '/^\d+$/', $quantityItems ) !== 1) {
            throw new InvalidArgumentException( sprintf( 'Items quantity should be a non-negative integer (%s)',
                $quantityItems ) );
        }

        $this->quantityItems = intval( $quantityItems );

        return $this;
    }
@param  int $quantityItems

@return $this