You are contracted to complete the data system for Citywide Taxi Company. Now, the information for each taxi is expanded to include: taxi id (such as CTC0001), the driver’s name, the maker of the Car (such as Ford), the model of the car (such as Escape), the Color of the Car (such as Black), the license number (such as HXT 4578), the number of passages the car served in the entire shift (integer type, this field will be left empty for this project).

Question 12. [15 MARKS] In this question, you will develop two classes to keep track of airplanes and flights. Here is the header and docstring for class Airplane. class Airplane: Information about a particular airplane including the model, the serial number, the number of seats, and the number of miles travelled. Part (a) [2 MARKS] Complete method __init_for class Airplane. Note: you will most likely not need all of the space on this page. def __init__(self, plane_model, serial_num, num_seats, miles_travelled): (Airplane, str, str, int, float) Record the airplane's model plane_model, serial number serial_num, the number of seats, and the distance travelled miles_travelled. >>> airplane - Airplane('Boeing 747', '19643', 366, 45267.7) >>> airplane.model 'Boeing 747 >>> airplane serial 19643 >>> airplane. seats 366 >>> airplane.miles 45267.7

Carol holds a two-digit number X and wants Alice and Bob to recover the number. She gives them the following information.

• Both Alice and Bob know that the number held by Carol is one of the following.

• 21  26
• 31  32  35
• 42  44
• 52  54  57
• 62  67

• Alice knows the number of ones of X but not the number of tens.
• Bob knows the number of tens of X but not the number of ones.

Alice and Bob exchange the following messages.

1. (a)  Bob to Alice: ’You might know X’.
2. (b)  Alice to Bob: ’I did not, but, after what you have said, I do’.

Based on the above information, please answer the following questions. For each question, please accompany your answer with a short explanation of why your believe your answer is correct. Marks will not be awarded for answers without any explanation.

1. (a)  Based on the statement of Bob it is possible to narrow down candidates for the number of tens from the initial five possibilities down to just two. What are these two possibilities? (7 marks)
2. (b)  Based on the ’I did not’ statement of Alice, the number of candidates for X can be narrowed down to just three. What are these candidates (6 marks)
3. (c)  The remaining part of Alice’s statement allows to identify X precisely. What is X? (7 marks)

His assignment is the next step to enhance your Programming Project 1 and Homework 3 works. As for 
now, you can keep the inventory in a file and upload it to the array available for your program. You have 
three classes for each type of products. It is time to think about how to improve the data model – all 
three types have enough in common to be child classes of one parent class.
Thus, the first thing to do is create a superclass and make three product type classes subclasses. Then, 
move as many members (fields and methods) from Type X, Y, and Z product classes to a superclass as 
possible. Change the constructors appropriately. 
The advantage of inheritance is the ability to create an array of superclass objects to be filled with 
objects of different subclasses. Thus, your inventory is in one array. Use the product’s index in the array 
to build the product’s ID (I would recommend starting with 1). In the superclass, create a static variable 
that holds the number of products available in the inventory. It must grow as reading from the file 
progresses.
Override a default toString() method for a superclass such that it shows product ID, name, regular 
price, and type.
At this moment, make sure that all modifications you have made keep your application alive and 
working.
The next step is to add three new classes to the project: 
• Create a class to represent the user – hardware store customer. You must decide what members 
this class needs. Ask the user to input necessary information.
• You may notice that the date of the year is a complicated piece of data. Create a class Date that 
converts a string of the form of “mm/dd/yyyy” into an object with three fields – month, day, and 
year. The class constructor may do this job, but do not forget to check the string for correctness.
Once you have this class ready, input the date as a string with the following converting into an 
object of type Date. Remember, if you read a string from the keyboard after a number, you 
may need to handle the new line symbol left in the input buffer.
• The result of your application is an order that must have the customer’s information, the date, 
the product information, and the total amount to pay. Thus, the third class to add is the class 
Order. When all the information is collected, the order is ready to be created and printed out. 
Outputting the order is the primary behavior of an object of type Order, and it is the final step 
of your application. Thus, class Order aggregates the customer’s info, date, product info, and 
total. Please note that Type X and Type Y products need only regular price and amount to 
calculate the total, while Type Z products must also consider the date.
The input and output examples for Types Y and Z are
User: Vladimir Kuperman
The inventory:
1 Light Bulb 60W 3.0 Type X
2 Light Bulb 100W 5.99 Type X
3 Steel Bolt M5 0.15 Type Y
4 Steel Bolt M8 0.25 Type Y
5 Hose 25 feet 10.0 Type Z
6 Hose 50 feet 15.0 Type Z
Your choice: 3
Number of units: 1000
What is the purchasing date? (mm/dd/yyyy)
12/12/2021
*********************************
Date 12/12/2021
*********************************
Vladimir Kuperman
Your item: 
+----+--------------+------+----+
|ID | Name |Price |Type|
+----+--------------+------+----+
|3 Steel Bolt M5 0.15 Y |
+----+--------------+------+----+
in the amount of 1000
*If you buy more than 1500 units you would pay $0.14 per unit.
*********************************
Your total: 127 dollars 50 cents
Save to file? (Y/N) Y
User: Vladimir Kuperman
The inventory:
1 Light Bulb 60W 3.0 Type X
2 Light Bulb 100W 5.99 Type X
3 Steel Bolt M5 0.15 Type Y
4 Steel Bolt M8 0.25 Type Y
5 Hose 25 feet 10.0 Type Z
6 Hose 50 feet 15.0 Type Z
Your choice: 5
Number of units: 10
What is the purchasing date? (mm/dd/yyyy)
10/12/2021
*********************************
Date 10/12/2021
*********************************
Vladimir Kuperman
Your item: 
+----+--------------+------+----+
|ID | Name |Price |Type|
+----+--------------+------+----+
|5 Hose 25 feet 10.0 Z |
+----+--------------+------+----+
in the amount of 10
*********************************
Your total: 70 dollars 0 cents
Save to file? (Y/N) Y
Program requirements
The program must have one superclass and three subclasses for three types of products according to 
the description given in Programming Project 1. 
The program must read the inventory from the file into one array for all three types of products. Each 
element of the array must be an object of one of the subclasses according to the information in the file. 
Product ID must be formed automatically using a static variable.
The user must be registered in the system, and the corresponding object must be created. Then, the
user chooses a product from the list, specifies an amount and the date of planned purchasing.
The date, user, product, amount, and the total must be aggregated in an object of type Order and 
outputted.
For this assignment, it is sufficient to output the order to the console. However, additional saving the 
order in the file will be considered as a plus.
The test plan must be developed for the program. Consider and test different inputs that may cause 
errors: incorrect file records, wrong date format, invalid user’s choice.
You have four weeks and three submission attempts for this assignment. Here is the suggested scenario 
on how to plan your work: