Как исправить появление "еды" на змейке?

from tkinter import *
import random
 
GAME_WIDTH = 800
GAME_HEIGHT = 500
SPEED = 130
SPACE_SIZE = 20
BODY_PARTS = 3
SNAKE_COLOR = '#00ff00'
FOOD_COLOR = '#ff0000'
BACKGROND_COLOR = '#ffffff'
 
 
class Snake:
 
    def __init__(self):
        self.body_size = BODY_PARTS
        self.coordinates = []
        self.squares = []
 
        for i in range(0, BODY_PARTS):
            self.coordinates.append([0, 0])
 
        for x, y in self.coordinates:
            square = canvas.create_rectangle(x, y, x + SPACE_SIZE, y + SPACE_SIZE, fill=SNAKE_COLOR, tag='snake')
            self.squares.append(square)
 
 
class Food:
 
    def __init__(self):
        x = random.randint(0, (GAME_WIDTH / SPACE_SIZE) - 1) * SPACE_SIZE
        y = random.randint(0, (GAME_HEIGHT / SPACE_SIZE) - 1) * SPACE_SIZE
 
        self.coordinates = [x, y]
 
        canvas.create_oval(x, y, x + SPACE_SIZE, y + SPACE_SIZE, fill=FOOD_COLOR, tag='food')
 
 
def next_turn(snake, food):
    x, y = snake.coordinates[0]
 
    if direction == 'up':
        y -= SPACE_SIZE
 
    elif direction == 'down':
        y += SPACE_SIZE
 
    elif direction == 'left':
        x -= SPACE_SIZE
 
    elif direction == 'right':
        x += SPACE_SIZE
 
    snake.coordinates.insert(0, (x, y))
 
    square = canvas.create_rectangle(x, y, x + SPACE_SIZE, y + SPACE_SIZE, fill=SNAKE_COLOR)
 
    snake.squares.insert(0, square)
 
    if x == food.coordinates[0] and y == food.coordinates[1]:
 
        global score
 
        score += 1
 
        label.config(text='Счет: {}'.format(score))
 
        canvas.delete('food')
 
        food = Food()
 
    else:
        del snake.coordinates[-1]
 
        canvas.delete(snake.squares[-1])
 
        del snake.squares[-1]
 
    if check_collision(snake):
        game_over()
 
    else:
        window.after(SPEED, next_turn, snake, food)
 
 
def change_direction(new_direction):
    global direction
 
    if new_direction == 'left':
        if direction != 'right':
            direction = new_direction
 
    elif new_direction == 'right':
        if direction != 'left':
            direction = new_direction
 
    elif new_direction == 'up':
        if direction != 'down':
            direction = new_direction
 
    elif new_direction == 'down':
        if direction != 'up':
            direction = new_direction
 
 
def check_collision(snake):
    x, y = snake.coordinates[0]
 
    if x < 0 or x >= GAME_WIDTH:
        return True
    elif y < 0 or y >= GAME_HEIGHT:
        return True
 
    for body_part in snake.coordinates[1:]:
        if x == body_part[0] and y == body_part[1]:
            return True
 
    return False
 
def game_over():
    canvas.delete(ALL)
 
    canvas.create_text(canvas.winfo_width() / 2, canvas.winfo_height() / 2,
                       font=('Arial', 30), text='Игра завершена', fill='red', tag='gameover')
 
 
window = Tk()
window.title('Змейка')
window.resizable(False, False)
 
score = 0
direction = 'down'
 
label = Label(window, text='Счет:{}'.format(score), font=('Arial 40'))
label.pack()
 
canvas = Canvas(window, bg=BACKGROND_COLOR, height=GAME_HEIGHT, width=GAME_WIDTH)
canvas.pack()
 
window.update()
 
window_width = window.winfo_width()
window_height = window.winfo_height()
screen_width = window.winfo_screenwidth()
screen_height = window.winfo_screenheight()
 
x = int((screen_width / 2) - (window_width / 2))
y = int((screen_height / 2) - (window_height / 2))
 
window.geometry(f'{window_width}x{window_height}+{x}+{y}')
 
window.bind('<Left>', lambda event: change_direction('left'))
window.bind('<Right>', lambda event: change_direction('right'))
window.bind('<Up>', lambda event: change_direction('up'))
window.bind('<Down>', lambda event: change_direction('down'))
 
snake = Snake()
food = Food()
 
next_turn(snake, food)
 
window.mainloop()