Class variable

There are six class variables i$.$e$.$ variables that are shared by all objects of this class

$\_\_$prices

This is a python dict that contains the grocery items as well as their unit price. This is defined as follows:

$\_\_$prices $=\{$ 'apple': $1\mathrm{.}8,$ 'bread': $2\mathrm{.}2,$ 'milk': $4\mathrm{.}9,$ 'pepper': $1\mathrm{.}2\}$

$\_\_$sale$\_$items

This is a list that contains all the items that are on sale in this period. A discount of $15\%$ is applied to the price of each item in this collection. This is defined as follows:

$\_\_$sale$\_$items $=$ 'apple banana'.split$()$

Four other class variable that are define as follows:

$\_\_$discount$\_$threshold $=6$

When the total cost of a purchase exceeds this amount then a discount is applied to the cost

$\_\_$default$\_$price $=2\mathrm{.}50$

If an item is not found in the $\_\_$prices dictionary, then this will be the default price

$\_\_$volume$\_$discount $=0\mathrm{.}9$

This is the rate of discount when the total cost exceeds the discount$\_$threshold

$\_\_$sales$\_$discount $=0\mathrm{.}85$

This is the rate of discount on an item if this item is in the $\_\_$sales$\_$time list.

Constructor

The constructor takes two argument that represents the name of the shopper and the amount of money she has. It assigns the argument to appropriate instance variable. It also creates an empty list to store the purchases.

Each purchase is a single tuple comprising of the name of the item and the price actually paid for the item.

Instance property

There is a single instance property that returns the name of this shopper object

Class method

There are three class methods:

$1.$ One that returns the price list.

$2.$ One that returns the list of sale items.

$3.$ One that adds a new item to the sale items list.

Instance method

There are two instance method:

purchase

This method takes a list of items to be purchase. It calculates the total price of the purchase by processing each item in the argument as show below:

The price of an item is obtained from the price list. If it is not found in the price list then the default price is used. $[$How to determine if an item in not in the dict$]$

If the item is in the sales list then a discount is applied to the price

The item as well as the result price is added to the list as a tuple. $[$How to create a tuple with name and price and how to add the tuple to the list$]$

When all the items are processed, if the final cost is over the credit threshold, then a discount is applied to this amount and then subtracted from the amount of money this object has left over.

$\_\_$str$\_\_$

This method returns a string representing this object i$.$e$.$ the name, cash and all its purchases pertaining to this shopper.

How to do this assignment.

From the above description and test harness and the result output below, try to deduce the definition of the Shopper class. Code this class in a jupyter notebook and copy the test harness to a cell below. Execute the notebook and ensure that the output matches EXACTLY with the output on the following page.

You must use python f$-$strings for your output.

Documentation.

Because the code is so simple no code documentation is required, however you must put your name and the current date somewhere at the top of your code.

How to submit this assignment.

Make the notebook shareable and submit the link to the course dropbox.

See the course documentation on deadlines.