Concept of Object Oriented Programs in Python

def Demo:
def __init__(self):
    __a = 1
    self.__b = 1
    self.__c__ = 1
    __d__= 1

class A:
    def __init__(self,x=3):
        self._x = x        
class B(A):
    def __init__(self):
        super().__init__(5)
    def display(self):
        print(self._x)
def main():
    obj = B()
    obj.display()
 
main()