Python Yılan Oyunu Problemi

import pygame
import random
from pygame.locals import *
from time import sleep
pygame.init()
pencerem=pygame.display.set_mode((800,600))
WHITE=(255,255,255)
BLACK=(0,0,0)
RED=(255,0,0)
GREEN=(0,255,0)
knmx=60
knmy=60
sagx=20
asagiy=20
yemx=100
yemy=100
haritasol=False
haritasag=False
haritayuk=False
haritaasg=False
yembyk=10
saga=True
sola=False
asg=False
yuk=False
hiz=10
tailsize=2
uyku=0.05
konum=[knmx,knmy]
gercekhiz=0.02 #ters orantı
def yon(x):
            if int(x)==273 and (saga or sola)==True and (yuk and asg)==False:
                a=True
                b=False
                c=False
                d=False
                return a,b,c,d
            elif int(x)==274 and (saga or sola)==True and (yuk and asg)==False:
                a=False
                b=False
                c=False
                d=True
                return a,b,c,d
            elif int(x)==275 and (saga and sola)==False and (yuk or asg)==True:
                a=False
                b=True
                c=False
                d=False
                return a,b,c,d
            elif int(x)==276 and (saga and sola)==False and (yuk or asg)==True:
                a=False
                b=False
                c=True
                d=False
                return a,b,c,d
            else:
                return yuk,saga,sola,asg
def hareket():
    global n,m
    if yuk==True:
        for i in range(1):
            n=knmy-hiz
            m=knmx
            sleep(uyku)
            return n,m
    if asg==True:
        for i in range(1):
            n=knmy+hiz
            m=knmx
            sleep(uyku)
            return n,m
    if sola==True:
        for i in range(1):
            m=knmx-hiz
            n=knmy
            sleep(uyku)
            return n,m
    if saga==True:
        for i in range(1):
            m=knmx+hiz
            n=knmy
            sleep(uyku)
            return n,m           
while True:
    pencerem.fill(BLACK)
    for i in range(1):
        bas=pygame.draw.rect(pencerem, RED, (knmx,knmy,sagx,asagiy))
        konum.append=[knmx,knmy]
        
                
            
        for olay in pygame.event.get():
            if olay.type==QUIT:
                pygame.quit()
            elif olay.type==KEYDOWN:
                kolay=olay.key
                yuk,saga,sola,asg=yon(kolay)       
        sleep(0.1)
        knmy,knmx=hareket()
        if knmx==800 and saga:
            knmx=0
        elif knmx==0 and sola:
            knmx=800
        elif knmy==0 and yuk:
            knmy=600
        elif knmy==600 and asg:
            knmy=0
        sleep(gercekhiz)
    
    pygame.display.flip()