inheritance_example

class First:
    def __init__(self, a: int, b: int):
        self.a = a
        self.b = b
        self.results = []

    def sum_numbers(self):
        result = self.a + self.b
        self.results.append(result)
        return result

    def subtract_numbers(self):
        result = self.a - self.b
        self.results.append(result)
        return result


# Inheritance
class Second(First):
    pass


class Third(Second):
    pass


class Fourth(Third):
    pass


print("----------First class----------")
obj = First(5, 4)
print(obj.sum_numbers())
print(obj.subtract_numbers())
print(obj.results)

print("----------Second class----------")
obj2 = Second(3, 2)
print(obj2.sum_numbers())
print(obj2.subtract_numbers())
print(obj2.results)

print("----------Third class----------")
obj3 = Third(20, 10)
print(obj3.sum_numbers())
print(obj3.subtract_numbers())
print(obj3.results)

print("----------Fourth class----------")
obj4 = Fourth(10, 5)
print(obj4.subtract_numbers())
print(obj4.sum_numbers())
print(obj4.results)