requirement from research organization nowwe get another rule from the research organization as belowwe do not want to store radius as instance variableinstead convert radius into diameter and save it as instance variable in the dictionary notethis condition will raise following two problemsmain problem here is thatother users already started using this class and have access to attribute 'radiusnowif we replace the key 'radiuswith 'diameter'then their code will break immediately alsowe need to update all our code as everything is calculated based on radiusand we are going to remove these attribute from diameter this is the main reason for hiding attributes in java and ++as these languages have no easy solution for this hencethese languages use getter and setter method but in python this problem can be solved using @property @property is used to convert the attribute access to method access in the other wordsas radius will be removed from instance variable list after meeting the need of the organizationtherefore it can not be used anymore but@property decorator will convert the attribute access to method accessi the dot operator will check for methods with @property as well in this waythe codes of other users will not breakas shown next pythonic py import math import time class ring(object)""here we will see the actual logic behind various pieces of python language instancesvariablesmethod and @property etc alsowe will see the combine usage of these pieces to complete design with agile methodology "" class variables date time strftime("% -% -% "time gmtime()today' date "yyyy-mm-ddcenter center of the ring def __init__(selfdate=datemetal="copper"radius= price= quantity= )""init is not the constructorbut the initializer which initialize the instance variable self is the instance __init__ takes the instance 'selfand populates it with the radiusmetaldate etc and store in dictionary self radiusself metal etc are the instance variable which must be unique "" self date date self metal metal self radius radius self price price self quantity quantity (continues on next page @property