(continued from previous page""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 def cost(self)return self price self quantity def area(self)return math pi self radius** lets check the functionality of the above codepython - pythonic py note that we used '-ioptiontherefore there is no need to import the class 'ringas shown in below coder ring(no paratmer pass therefore default values will be used date instance variable ' radius instance variable center class variable cost(class method area(class method alsowe can modify the instance and class variables values as shown belowr price current value quantity cost( quantity= modify instance variable cost(price is changed to center modify class variable center notethe value of the variables are stored in the dictionarywhose contents can be seen using '__dict__' simple data structure to classes