Adding Transaction History

For many reasons, it's essential we track the transactions made in our store. Let's create a Transaction class to contain the details of each transaction that we processed in the previous tutorial.

class Transaction:

    def __init__(
        self.num_items: int,
        self.original_price: float,
        self.discounted_price: float = 0.0
    ) -> None:
        self.num_items = num_items
        self.original_price = original_price
        self.discounted_price = discounted_price

Add a transactions attribute to the class, and update the sell method to use this object:

class Store:

    def __init__(name: str, inventory: int, balance: float, price: float) -> None:
        self.name = name
        self.inventory = inventory
        self.balance = balance
        self.price = price
        self.transactions = []  # Initialize an empty list to store transactions

    def sell(self, num_items: int, discount: float = 0.0) -> None:
        if num_items > self.inventory:
            raise Exception("Not enough inventory to sell the requested number of items.")

        transaction = Transaction(
            num_items=num_items,
            original_price=self.price,
            discounted_price=self.price * (1 - discount)
        )

        self.transactions.append(transaction)

        # Read num_items and price from the transaction object
        self.inventory -= transaction.num_items
        self.balance += transaction.num_items * transaction.discounted_price

Now every time a sale is made, a new Transaction object is created and added to the transactions list. You can view the transactions on our sample store.

store.sell(num_items=10, discount=0.1)
store.sell(num_items=3)

print(len(store.transactions))  # Output: 2