code

import turtle
import time
from turtle import Turtle

delay = 0.1

# screen setup
wn = turtle.Screen()
wn.title("Snake Game")
wn.bgcolor("green")
wn.setup(width=800, height=600)
wn.tracer(0)

# Snake head
head = turtle.Turtle()
head.speed(0)
head.shape("square")
head.color("black")
head.penup()
head.goto(0, 0)
head.direction("stop")

def go_up():
    head.direction = "up"

def go_down():
    head.direction = "down"

def go_left():
    head.direction = "left"

def go_right():
    head.direction = "right"

def move():
    if head.direction == "up":
        y = head.ycor()
        head.sety(y + 20)
    if head.direction == "down":
        y = head.ycor()
        head.sety(y - 20)
    if head.direction == "left":
        x = head.xcor()
        head.setx(x - 20)
    if head.direction == "right":
        x = head.xcor()
        head.setx(x + 20)

wn.listen()
wn.onkeypress(go_up(), "w")
wn.onkeypress(go_down(), "s")
wn.onkeypress(go_left(), "a")
wn.onkeypress(go_right(), "d")


while True:
    wn.update()
    move()
    time.sleep(delay)

# I needed to put another while because it said that code is unrechable
while True:
    wn.mainloop()