From: Сергей

ball.py

import pygame

from game_object import GameObject


class Ball(GameObject):
    def __init__(self, x, y, r, color, speed):
        GameObject.__init__(self, x - r, y - r, r * 2, r * 2, speed)
        self.radius = r
        self.diameter = r * 2
        self.color = color

    def draw(self, surface):
        r = pygame.draw.circle(surface, self.color, self.center, self.radius)

    def update(self):
        super().update()