I'm doing tutorial for platform game but my Pygame window displays a black screen.

I don't know how to solve this.

I tried closing and opening Visual Studio Code again but nothing happens.

```py
import pygame

SCREEN_SIZE = (700,500)
DARK_GREY = (50,50,50)
OGURKOWY = (21,179, 58)

pygame.init()

screen = pygame.display.set_mode(SCREEN_SIZE)
pygame.display.set_caption("Platformówka")
player_image = pygame.image.load("ogurek\doggo.png")
player_x = 300
platforms = [
  pygame.Rect(100,300,400,50),
  pygame.Rect(100,250 ,50,50),
  pygame.Rect(450,250,50,50),
  pygame.Rect(450,250,100,50)
]

running = True

while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    keys = pygame.key.get_pressed()
    if keys[pygame.K_a]:
        player_x -= 2
    if keys[pygame.K_a]:
        player_x += 2   
    #tło
    screen.fill(DARK_GREY)
    #platformy

for p in platforms: 
    pygame.draw.rect(screen, (OGURKOWY), p)
    #gracz
    screen.blit(player_image, (player_x,100))
    # 
    pygame.display.flip()

pygame.quit()

```