writing_4.py

class Receipt:
    def __init__(self, item, cost):
        self.item = item
        self.cost = cost
    
    def receipt_msg(self):
        return f"{self.item}, ${round(self.cost, 2)}"

    def deliver(self):
        msg = self.receipt_msg()
        print(f"Printing receipt... {msg}")
    
class EmailReceipt(Receipt):
    def __init__(self, item, cost, customer_email):
        super().__init__(item, cost)
        self.customer_email = customer_email
    
    def deliver(self):
        msg = self.receipt_msg()
        print(f"Emailing receipt to [{self.customer_email}]... {msg}")

regular_receipt = Receipt("Subscription", 120)
regular_receipt.deliver()
    # Printing receipt... Subscription, $120

paperless_receipt = EmailReceipt("Subscription", 120,                  
                                 "charles@diffengine.ai")
paperless_receipt.deliver()
    # Emailing receipt to [charles@diffengine.ai]... Subscription, $120