python class method vs instance method code example

Example 1: instance method in python

# Instance Method Example in Python 
class Student:
    
    def __init__(self, a, b):
        self.a = a
        self.b = b 
    
    def avg(self):
        return (self.a + self.b) / 2

s1 = Student(10, 20)
print( s1.avg() )

Example 2: cls in python

import os
clear = lambda: os.system('cls')

Example 3: Class vs. Instance python3

class Person:
    def __init__(self,initialAge):
        # Add some more code to run some checks on initialAge
        if initialAge < 0:
            self.age = 0
            print("Age is not valid, setting age to 0.")
        else:
            self.age = initialAge
    def amIOld(self):
        # Do some computations in here and print out the correct statement to the console
        if self.age < 13:
            print("You are young.")
        elif self.age>=13 and self.age <18:
            print("You are a teenager.")
        else:
            print("You are old.")
    def yearPasses(self):
        # Increment the age of the person in here
        self.age += 1