1. Classes: A class definition is like a blueprint (receipe) for each of the objects of that class A class specifies a set of data attributes and methods for the objects of that class The values of the data attributes of a given object make up its state The behavior of an object depends on its current state and on the methods that manipulate this state The set of a class’s methods is called its interfaceA simple class definition example is a 6-sided Die:"""File: simple_die.pyDescription: This module defines a six-sided Die class."""from random import randintclass Die(object): """This class represents a six-sided die.""" def __init__(self): """The initial face of the die.""" self._currentRoll = randint(1, 6) def roll(self): """Resets the die's value to a random number between 1 and 6.""" self._currentRoll = randint(1, 6) def getRoll(self): """Returns the face value of the die.""" return self._currentRoll def __str__(self): """Returns the string representation of the die.""" return str(self._currentRoll) Consider the following script to test the Die class and its associated output:Classes in Python have the following characteristics: all class attributes (data attributes and methods) are public by default, unless your identifier starts with a singleunderscores, e.g, self._currentRoll  all data types are objects, so they can be used as inherited base classes objects are passed by reference when used as parameters to functions all classes have a set of standard methods provided, but may not work properly (__str__, __doc__, etc.) most built-in operators (+, -, *, <, >, ==, etc.) can be redefined for a class. This makes programming withobjects a lot more intuitive. Data Structures Name:_______________________Lecture 4 Page 1# testDie.py - script to test Die classfrom simple_die import Diedie1 = Die()die2 = Die()print 'die1 =', die1 #calls __str__print 'die2 =', die2printprint 'die1.getRoll() = ', die1.getRoll()print 'die2.getRoll() = ', die2.getRoll()die1.roll()print 'die1.getRoll() = ', die1.getRoll()print 'str(die1): ' + str(die1)print 'die1 + die2:', die1.getRoll() + die2.getRoll()>>> die1 = 2die2 = 5die1.getRoll() = 2die2.getRoll() = 5 die1.getRoll() = 3str(die1): 3die1 + die2: 8>>>Three important features of Object-Oriented Programming (OOP) to simplify programs and make themmaintainable are:1. encapsulation - restricts access to an object's data to its own methods helps to prevent indiscriminant changes that might cause an invalid object state (e.g., 6-side die with a of roll 8)2. inheritance - allows one class (the subclass) to pickup data attributes and methods of other class(es) (the parents) helps code reuse since the subclass can extend its parent class(es) by adding addition data attributes and/ormethods, or overriding (through polymorphism) a parent's methods 3. polymorphism - allows methods in several different classes to have the same names, but be tailored for each class helps reduce the need to learn new names for standard operations (or invent strange names to make them unique)Consider using inheritance to extend the Die class to a generalized AdvancedDie class that can have any numberof sides. The interface for the AdvancedDie class are:Consider the following script and associated output:die1 = Number of Sides=100 Roll=32die2 = Number of Sides=100 Roll=76die3 = Number of Sides=6 Roll=5die1.getRoll() = 32die1.getSides() = 100die1.getRoll() = 70die2.getRoll() = 76die1 == die2: Falsedie1 < die2: Truedie1 > die2: Falsedie1 <= die2: Truedie1 >= die2: Falsedie1 != die2: Truestr(die1): Number of Sides=100 Roll=70die1 + die2: 146Help on class AdvancedDie in moduleadvanced_die:...Data Structures Name:_______________________Lecture 4 Page 2Returns a string representation for the AdvancedDie. Directly as:str(myDie)or indirectly as:print myDie__str__Allows the direct addition of AdvancedDie objects, and returns theinteger sum of their current roll values.sum = myDie + otherDie__add__Allows the comparison operations (>, <, ==, etc.) to work correctly forAdvancedDie objects. if myDie == otherDie:__cmp__Rerolls the die randomly myDie.roll()roll Returns the number of sides on the die myDie.getSides()getSides Returns the current roll of the die myDie.getRoll()getRoll Constructs a die with a specified number of sides and randomly rolls it (Default of 6 sides if no argument supplied)myDie =AdvancedDie(8)__init__Description Example UsageMethod Detail Descriptions of the AdvancedDie Class Methods# testDie.py - script to test AdvancedDie classfrom advanced_die import AdvancedDiedie1 = AdvancedDie(100)die2 = AdvancedDie(100)die3 = AdvancedDie()print 'die1 =', die1 #calls __str__print 'die2 =', die2print 'die3 =', die3print 'die1.getRoll() = ', die1.getRoll()print 'die1.getSides() =', die1.getSides()die1.roll()print 'die1.getRoll() = ', die1.getRoll()print 'die2.getRoll() = ', die2.getRoll()print 'die1 == die2:', die1==die2print 'die1 < die2:', die1<die2print 'die1 > die2:', die1>die2print 'die1 <= die2:', die1<=die2print 'die1 >= die2:', die1>=die2print 'die1 != die2:', die1!=die2print 'str(die1): ' + str(die1)print 'die1 + die2:', die1 + die2help(AdvancedDie)The AdvancedDie class that inherits from the Die superclass. """File: advanced_die.pyDescription: Provides a AdvancedDie class that allows for any number of sidesInherits from the parent class Die in module die_simple"""from simple_die import Diefrom random import randintclass AdvancedDie(Die): """Advanced die class that allows for any number of sides""" def __init__(self, sides = 6): """Constructor for any sided Die that takes an the number of sides as a parameter; if no parameter given then default is 6-sided.""" # call Die parent class constructor Die.__init__(self) self._numSides = sides self._currentRoll = randint(1, self._numSides) def roll(self): """Causes a die to roll itself -- overrides Die class roll""" self._currentRoll = randint(1, self._numSides) def __cmp__(self, rhs_Die): """Overrides the '__cmp__' operator for Dies, to allow for to allow for a deep comparison of two Dice""" if self._currentRoll < rhs_Die._currentRoll: return -1 elif self._currentRoll == rhs_Die._currentRoll: return 0 else: return 1 def __str__(self): """Returns the string representation of the AdvancedDie.""" return 'Number of Sides='+str(self._numSides)+' Roll='+str(self._currentRoll) def __add__(self, rhs_Die): """Returns the sum of