# Class
class Asteroid():
    def __init__(self,...):
        self.x = ...
        self.y = ...
        self.brightness = ...
        self.update_time = ... # time between next move
        self.time_last_update = ...
        self.is_active = True # optional, see info for update-Method

    def update(self):
        """
        Method is called each time in game loop.
        In here, check if enough time has passed s.t. asteroid moves to next position.
        If yes, move asteroid.
        
        Somewhere need to check if asteroid is out of screen. Can be done here or outside in game loop.
        If done here, class need attribute self.is_active = False/True
        """
        pass

    def display(self):
        """
        displays asteroid
        """
        pass

# Create object of class asteroid
a = Asteroid(...)