Concept of Object Oriented Programs in Python

class A:
    def __init__(self, x= 1):
        self.x = x
class der(A):
    def __init__(self,y = 2):
        super().__init__()
        self.y = y
def main():
    obj = der()
    print(obj.x, obj.y)
main()

class Demo:
    def __check(self):
        return " Demo's check "
    def display(self):
        print(self.check())
class Demo_Derived(Demo):
    def __check(self):
        return " Derived's check "
Demo().display()
Demo_Derived().display()

class A:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def __str__(self):
        return 1
    def __eq__(self, other):
        return self.x * self.y == other.x * other.y
obj1 = A(5, 2)
obj2 = A(2, 5)
print(obj1 == obj2)

class Test:
    def __init__(self):
        self.x = 0
class Derived_Test(Test):
    def __init__(self):
        Test.__init__(self)
        self.y = 1
def main():
    b = Derived_Test()
    print(b.x,b.y)
main()