In this assignment, you are required to design, implement and test a program that can be used

to manage a simple shopping cart system with shopping records, which are stored in a list.

Your program must provide an interactive design that allows the user to:

$$ create new shopping records and add them to the shopping cart system;

$$ display all shopping records with details;

$$ calculate the total cost of all the records or the records of searching outcome;

$$ search for specific shopping records in all records;

The program is to be implemented by Python and as a $.$ipynb file running on a Jupyter notebook.

Shopping cart system

Figure $1$ illustrates the catalogue provided for customers before they use your program. You

do not need to add the picture or table of catalogue into your program. The data in the catalogue

for your program have been added to the product$\_$list and price$\_$list of the $$Product and price

lists.txt$.$ Please directly copy the text and paste it to your $.$ipynb file without modification.

Figure $1$: Catalogue

Figures $2$ and $3$ on the next page illustrate the shopping cart system with sample outcomes of

show$\_$record$()$ and sorting. Please use this illustration as the reference for the following

descriptions.

Shopping records

This program will hold or encapsulate data for the product code, product name, price, quantity

and shipping method. With respect to each of the attributes, a shopping record can be

represented like the following sample:

$"2/$Tea Set$/$High$/39\mathrm{.}95/1/$Pick$-$up$"$

This can be deciphered as: for this shopping record, the product code is $2,$ the product name

is Tea Set, its value is high $($When the unit price of a product is no less than $$30,$ its value

is high. Otherwise, it is low$),$ unit price is $$39\mathrm{.}95,$ quantity is $1,$ shipping method is $$Pick$-$up$.$

You should create a global variable $-$ list $-$ to store all such shopping records. For the sake of

easy explanation, we refer to this variable by shopping$\_$record$\_$list in the rest of this document.

Some limitations must be imposed on the shopping records:

Product code must be "END"$($case sensitive$)$ or an integer number and only if:

$0<=$ code $<=39$;

Quantity must be an integer number and only if:

$0<$ quantity $<=49$;

Your Tasks

It is strongly suggested that the following approach is to be taken to design and implement the

program.

Interactive design

You should implement and test the Interactive design of the shopping cart system for users to

input value and obtain outputs. Input functions should be applied for users to enter shipping

method, product code and quantity.

The add$\_$record$()$ Function

You should design, implement and test a function to add a shopping record to the shopping cart

system. A shopping record will be added to the shopping cart system each time when all the

inputs $($product code, quantity and shipping method$)$ are valid. The program will continually

ask the user to input the record by three input functions until "END" $($case sensitive$)$ is input

for the product code. The function handles the following tasks:

$$ The "product code" is obtained by the first input function. Validate if the input for

"product code" is correct by using the function is$\_$valid$\_$code$()$ described below;

$$ If the valid "product code" is not "END". Collect corresponding product name and price

from the product$\_$list and price$\_$list according to "product code" for the shopping record;

$$ If the entered "product code" is "END". Stop the iteration and collect all the entered

records and then run the show$\_$records$()$ Function.

$$ The "quantity" is obtained by the second input function. Validate if the input for

"quantity" is correct by using the function is$\_$valid$\_$quantity$()$ described below;

$$ The "shipping method" is obtained by the third input function. Validate inputs are

"Pick$-$up$"$ and "Delivery", case insensitive.

$$ Add the shopping record into the shopping$\_$record$\_$list list if all data are valid,

otherwise, return an error message for each input function;

The is$\_$valid$\_$code$()$ Function

You should design, implement and test a function to validate the data input for the product code

attribute of a shopping record. The function should alert an error message and return false if

the input is invalid, otherwise, return true.

Refer to the product code section on page $2$ for what the function needs to check for validation.

The is$\_$valid$\_$quantity$()$ Function

You should design, implement and test a function to validate the data input for the quantity

attribute of a shopping record. The function should alert an error message and return false if

the input is invalid, otherwise; return true.

Refer to the quantity section on page $2$ for what the function needs to check for validation.

The show$\_$records$()$ Function

You should design, implement and test a function to show all existing records in the shopping

cart system. The function should access the shopping$\_$record$\_$list and print all existing

shopping records in an acceptable format as