Python - ShoppingCart

class ShoppingCart:

    def __init__(self):
        self.total = 0
        self.items = dict()
        #self.items = {}

    def add_item(self, item_name, quantity, price):
        self.total += quantity*price

        if item_name not in self.items:
            self.items[item_name] = quantity
        else:
            self.items[item_name] += quantity

# ---- test ----

cart = ShoppingCart()

cart.add_item('banana', 3, 4)
cart.add_item('banana', 5, 4) # add againg the same item
cart.add_item('orange', 2, 3)

print('total:', cart.total)
print('items:', cart.items)

# total: 38
# items: {'orange': 2, 'banana': 8}