class MyClass:
    def __init__(self, value):
        self.value = value
        
    def display_value(self):
        print(f"Value: {self.value}")
    
my_class_instance = MyClass(10)
my_class_instance.display_value()

    
class MySubClass(MyClass):
    def __init__(self, value, extra):
        super().__init__(value)
        self.extra = extra
        
    def display_extra(self):
        print(f"Extra: {self.extra}")
        
my_subclass_instance = MySubClass(20, "Hello")
my_subclass_instance.display_value()    
my_subclass_instance.display_extra()