please write this in python. $1.$ Dessert Shop Part $7$: Payment Method

Read all instructions carefully. Not following instructions will result in you not earning the credit you want for the assignment.

Objectives

Create an interface

Implement an interface

Define a type with a specific set of enumerated values

Problem

In Part $7,$ suppose you want to add functionality to your Dessert Shop application to identify what type of payment the customer will use. A line indicating the payment type will be added to the bottom of the receipt.

To do this, you will add an interface to your Dessert Shop application and update your receipt output as described below.

Possible ways to pay are CASH, CARD, PHONE.

Payable interface

Create a Protocol class Payable.

Define a type PayType whose only legal values are$\{$CASH$,$ CARD, PHONE$\}.$

Payable will include two methods:

get$\_$pay$\_$type$()$: PayType

set$\_$pay$\_$type$($payment$\_$method: PayType$)$

Raise a ValueError if get$\_$pay$\_$type returns anything other than one of these values. Similarly, raise an error if set$\_$pay$\_$type attempts to set a value that is not of of these values.

Changes to Order class

Implement the Payment interface. You decide how this is to be implemented and tested.

The default value for pay method in the constructor should be CASH.

Modify $\_\_$str$\_\_$ method to include payment type in the order as shown in the example run.

Changes DessertShop class

Add a method that

prompts the user for payment type as shown in the example run

validates the input

returns the payment type to the calling code to set the payment type before an order is printed.

Test Cases

Add pytest test cases to test the payment type of an Order. Create a new test file test$\_$order.py to hold these test cases. You only need $5$ test cases: $3$ to check for each valid payment type, one to check for trying to set an invalid value and one for trying to get $($return$)$ an invalid value.

We are not testing the user interface with automated test cases, just Order objects with new payment types.

Key Program Requirements

You have added a new Payable interface to your system.

The PDF receipt output has been modified to include the payment method as shown.

Your workspace includes all source files so far and two new files:

test$\_$order.py with cases for testing payment method

Payable interface is defined in file payable.py$.$

Example Run

$1$: Candy

$2$: Cookie

$3$: Ice Cream

$4$: Sunday

What would you like to add to the order? $(1-4,$ Enter for done$)$: $2$

Enter the type of cookie: Oatmeal Raisin

Enter the quantity purchased: $4$

Enter the price per dozen: $3\mathrm{.}45$

$1$: Candy

$2$: Cookie

$3$: Ice Cream

$4$: Sunday

What would you like to add to the order? $(1-4,$ Enter for done$)$:

$1$: Cash

$2$: Card

$3$: Phone

Enter payment method: $2$

$----------------------------------------------$Receipt$---------------------------$

Oatmeal Raisin Cookies $($Box$)$

$4$ cookies @ $$3\mathrm{.}45/$dozen: $$1\mathrm{.}15[$Tax: $$0\mathrm{.}08]$

Candy Corn $($Bag$)$

$1\mathrm{.}50$ lbs$.$ @ $$0\mathrm{.}25/$lb$.$: $$0\mathrm{.}38[$Tax: $$0\mathrm{.}03]$

Gummy Bears $($Bag$)$

$0\mathrm{.}25$ lbs$.$ @ $$0\mathrm{.}35/$lb$.$: $$0\mathrm{.}09[$Tax: $$0\mathrm{.}01]$

Chocolate Chip Cookies $($Box$)$

$6$ cookies @ $$3\mathrm{.}99/$dozen: $$2\mathrm{.}00[$Tax: $$0\mathrm{.}14]$

Pistachio Ice Cream $($Bowl$)$

$2$ scoops @ $$0\mathrm{.}79/$scoop: $$1\mathrm{.}58[$Tax: $$0\mathrm{.}11]$

Vanilla Sundae $($Boat$)$

$3$ scoops of Vanilla ice cream @ $$0\mathrm{.}69/$scoop

Hot Fudge topping @ $$1\mathrm{.}29$: $$3\mathrm{.}36[$Tax: $$0\mathrm{.}24]$

Oatmeal Raisin Cookies $($Box$)$

$2$ cookies @ $$3\mathrm{.}45/$dozen: $$0\mathrm{.}58[$Tax: $$0\mathrm{.}04]$

$---------------------------------------------------------------------------------$

Total number of items in order: $7$

Order Subtotals: $$9\mathrm{.}12[$Tax: $$0\mathrm{.}66]$

Order Total: $$9\mathrm{.}78$

$---------------------------------------------------------------------------------$

Paid with CARD