Остаток из текста ошибки

class ShopError(Exception):
    """Базовая ошибка магазина."""


class OutOfStockError(ShopError):
    def __init__(self, product_id, left):
        super().__init__(f"Товара {product_id} осталось {left} шт.")
        self.product_id = product_id
        self.left = left


STOCK = {1: 3, 2: 0}


def reserve(product_id, quantity):
    left = STOCK[product_id]
    if quantity > left:
        raise OutOfStockError(product_id, left)
    STOCK[product_id] = left - quantity


def handle_reserve(product_id, quantity):
    try:
        reserve(product_id, quantity)
    except OutOfStockError as e:
        return 409, {"product_id": e.product_id, "left": e.left}
    return 200, {}


print(handle_reserve(1, 5))