Kivy: Can you instantiate a custom widget from a python script

I've created a custom widget in a .kv file, but I need a way to create an instance of that custom widget in my python script like I would any other widget like a Label. Is there any way to do this, or any way to create something similar to a css class that could be referenced in a python file? This is my kivy code so far:

<News@Label>:
    font_size: 25
    color: 0, 0, 0, 1
    font_family: 'Serif'

And here's the python code where I'm trying to create an instance of the custom widget:

class BiteApp(App):
    def build(self):
        return MyGrid()
    
    def on_start(self):
        app = App.get_running_app()
        for story in range(len(newsScrape.getNewsGlobal())):
            app.root.ids.newsGrid.add_widget(Label(text=newsScrape.getNewsGlobal()[story], cls="News"))

I tried using "cls='News'" as a last-ditch effort, but that obviously didn't work out