Pygame Loop fix

pygame-fix.py

import pygame
from pygame.locals import *
import sys

pygame.init()

pygame.display.set_caption('Test')

mouse = pygame.mouse
fps_clock = pygame.time.Clock()

width = 640
height = 480

window = pygame.display.set_mode((width, height))

BLACK = pygame.Color(0, 0, 0)
WHITE = pygame.Color(255, 255, 255)

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

x1 = 20
y1 = 20
running = True

while running:
    keys = pygame.key.get_pressed()  # checking pressed keys
    window.fill(WHITE)
    for event in pygame.event.get():
        if event.type == QUIT:
            running = False
    if keys[pygame.K_w]:
        y1 -= 1
    if keys[pygame.K_s]:
        y1 += 1
    if keys[pygame.K_a]:
        x1 -= 1
    if keys[pygame.K_d]:
        x1 += 1
    pygame.draw.circle(window, BLACK, [x1, y1], 5)
    pygame.display.update()
    fps_clock.tick(60)

pygame.quit()
sys.exit()