so i've changed the window color to a white color, unfortunately its not updating, [it also returns an error](https://i.stack.imgur.com/BAHBd.png)

code:

```
import pygame

WIDTH, HEIGHT = 900, 500
WIN = pygame.display.set_mode((WIDTH,HEIGHT))
pygame.display = pygame.display.set_caption('PyGame Test')
WHITE = (255,255,255)
def main():
  run = True
  while run:
      for event in pygame.event.get():
          if event.type == pygame.QUIT:
              run = False

      WIN.fill(WHITE)
      pygame.display.update()

  pygame.quit()

if __name__ == '__main__':
  main()

```

what am i doing wrong?