似乎无法通过函数传递类变量

class MyClass:
    class_variable = "Hello"

    def update_class_variable(self, new_value):
        self.class_variable = new_value

obj = MyClass()
obj.update_class_variable("World")
print(obj.class_variable)  # Output: World

class MyClass:
    class_variable = "Hello"

    @classmethod
    def update_class_variable(cls, new_value):
        cls.class_variable = new_value

MyClass.update_class_variable("World")
print(MyClass.class_variable)  # Output: World

class MyClass:
    class_variable = "Hello"

MyClass.class_variable = "World"
print(MyClass.class_variable)  # Output: World