private function subTotalPrice()
    {
        return $this->items->sum(function ($item) {
            return bcmul($item['price'], $item['ammount'], $this->decimals);
        });
    }
private function subTotalPrice()
    {
        return $this->items->sum(function ($item) {
            return bcmul($item['price'], $item['ammount'], $this->decimals);
        });
    }
private function subTotalPrice ( ) { return $ this -> items -> sum ( function ( $ item ) { return bcmul ( $ item [ 'price' ] , $ item [ 'ammount' ] , $ this -> decimals ) ; } ) ; }
Return the subtotal invoice price.

@method subTotalPrice

@return int
Return the subtotal invoice price .