Can't pass kwargs to sub class in Kivy — TypeError: object.__init__() takes exactly one argument (the instance to initialize)

I’m very new to programming so forgive me if the solution here is obvious. I’ve done a fair bit of googling and haven’t been able to sort this problem out.
I’m trying to enable a subclass to accept any keyword arguments the base class can accept, as well as a few additional ones I want to pass, but I keep running into the following error: TypeError: object.init() takes exactly one argument (the instance to initialize).

If I comment out the keyword arguments not built into the base class (workout_title, last_completed, and lifts) the code runs no problem.

How do I allow the subclass to take my additional kwargs?

class SelectionBanner(GridLayout):
    def __init__(self, **kwargs) -> None:
        super().__init__(**kwargs)
    
        grid = GridLayout(
            rows = 3, 
            size_hint = (.8,1)
            )
        workout_title_label = Label(
            size_hint = (1,.33), 
            pos_hint = {"top": 1, "left": .5}, 
            text = "workout tile"
            )
        last_completed_label = Label(
            size_hint = (1,.33), 
            pos_hint = {"top": 1, "left": .5}, 
            text = "last_completed"
            )
        lifts_label = Label(
            size_hint = (1,.33), 
            pos_hint = {"top": 1, "left": .5}, 
            text = "lifts"
            )
        button = Button(
            size_hint = (.2, 1),
            text = "Click me!"
        )

        grid.add_widget(workout_title_label)
        grid.add_widget(last_completed_label)
        grid.add_widget(lifts_label)
    
        self.add_widget(grid)
        self.add_widget(button)

def build_selection_page(self):
    data = db.reference("/workout_templates").get()
    selection_page = self.root.ids['home_screen'].ids['top_layout']
    selection_page.add_widget(SelectionBanner(
        cols = 2, 
        padding = 10, 
        spacing = 10, 
        pos_hint = {"top": 1, "left": .5}, 
        size_hint = (1, .2),
        workout_title = "Workout B",
        last_completed = "Yesterday",
        lifts = "Bench and stuff"
        ))

>Solution :

Just add Properties for the new keyword arguments, like this:

class SelectionBanner(GridLayout):
    workout_title = StringProperty('')
    last_completed = StringProperty('')
    lifts = StringProperty('')

    def __init__(self, **kwargs) -> None:
        super().__init__(**kwargs)
    .
    .
    .