# Larger code run in a REPL


>>> class FirstClass:               # Define a class object
        def setdata(self, value):   # Define class's methods
            self.data = value       # self is the instance
        def display(self):
            print(self.data)        # self.data: per instance


>>> class SecondClass(FirstClass):                   # Inherits setdata
        def display(self):                           # Changes display
            print(f'Current value = "{self.data}"')


>>> class ThirdClass(SecondClass):                     # Inherit from SecondClass
        def __init__(self, value):                     # On "ThirdClass(value)"
            self.data = value
        def __add__(self, other):                      # On "self + other"
            return ThirdClass(self.data + other)
        def __str__(self):                             # On "print(self)", "str()"
            return f'[ThirdClass: {self.data}]'
        def mul(self, other):                          # In-place change: named
            self.data *= other


>>> class Person:
        def __init__(self, name, jobs, age=None):      # class = data + logic
            self.name = name
            self.jobs = jobs
            self.age  = age
        def info(self):
            return (self.name, self.jobs)