Pygame Game

import pygame

pygame.init()
screen = pygame.display.set_mode((900, 500))
pygame.display.set_caption('My game')
clock = pygame.time.Clock()
player = pygame.rect.Rect(10, 200, 20, 100)
bot = pygame.rect.Rect(885, 200, 20, 100)
ball = pygame.rect.Rect(445, 245, 10, 10)
running = True
player_speed_y = 0
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_UP:
                player_speed_y -= 1
            if event.key == pygame.K_DOWN:
                player_speed_y += 1

        if event.type == pygame.KEYUP:
            if event.key == pygame.K_UP:
                player_speed_y += 1
            if event.key == pygame.K_DOWN:
                player_speed_y -= 1

    player.y += player_speed_y
    screen.fill((0, 0, 0))
    pygame.draw.rect(screen, (20, 200, 20), player)
    pygame.draw.rect(screen, (200, 20, 20), bot)
    pygame.draw.ellipse(screen, (255, 255, 255), ball)
    pygame.display.flip()
    clock.tick(60)