#prompt the user by name and ask how many tickets they would like
tickets_required = input("How many tickets would you like,{}? ".format(user_name))
# Expect a ValueError(handle it appropriately )test it!
try:
    tickets_required = int(tickets_required)
    if tickets_required > tickets_remaining:
        raise ValueError("tickets available {} try again".format(tickets_remaining)
except ValueError as err:
    print("that's not a valid entry please {} try again".format(err))
else:
    #calculate the price(number if tickets * price)and assing it to a variable
    total_sale = tickets_required * TICKET_PRICE   

    #output the price to the screen
    print("the grand total is {} ".format(total_sale))

    #prompt the user is they want to proceed. Y/N?
    proceed = input("Do you want to continue Y/N?")
    #confirm purchase
    #TODO gather card payment details
    if proceed.lower() == "y":
        print("SOLD! Thank you for your Purchase!")
        #displays the remaining amount of ticket available for next sale
        tickets_remaining -= tickets_required
    else:
        print("Thanks you anyway {}".format(user_name))