大豬哥期末考為python貪吃蛇增加速度

from tkinter import *
import random
GAME_WIDTH,GAME_HEIGHT = 800, 400
SPEED = 1000    #時間單位千分之一
SPACE_SIZE, BODY_PARTS= 50, 3 #左邊變數 assigning value
SNAKE_COLOR = ["red","orange","yellow","green","blue","indigo", "purple"]
FOOD_COLOR = "white"
BACKGROUND_COLOR = "black"
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:
            i = random.randint(0,6)
            square = canvas.create_rectangle(x, y, x + SPACE_SIZE, y + SPACE_SIZE, fill=SNAKE_COLOR[i], tag="snake", width=20,outline='blue')
            self.squares.append(square)
class Food:
    def __init__(self):
        x = random.randint(0, int(GAME_WIDTH / SPACE_SIZE)-1) * SPACE_SIZE
        y = random.randint(0, int(GAME_HEIGHT / SPACE_SIZE) - 1) * SPACE_SIZE
        self.coordinates = [x, y]
        i = random.randint(0,6)
        canvas.create_oval(x,y, x+SPACE_SIZE, y+SPACE_SIZE, fill=FOOD_COLOR, tag="food",width=10,outline=SNAKE_COLOR[i])
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))
    i = random.randint(0,6) 
    square = canvas.create_rectangle(x, y, x + SPACE_SIZE, y + SPACE_SIZE, fill=SNAKE_COLOR[i])
    snake.squares.insert(0, square)
    if x == food.coordinates[0] and y == food.coordinates[1]:
        global score  #globe地球儀,全域變數
        score += 100; global SPEED; SPEED =SPEED -200 #用;分隔指令或換列
        label.config(text="大豬哥分數:{}".format(score))
        canvas.delete("food")
        food = Food()
    else:
        del snake.coordinates[-1]
        canvas.delete(snake.squares[-1])
        del snake.squares[-1]
    if check_collisions(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_collisions(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=('consolas',60), text="劉任昌增加速度", fill="red", tag="gameover")
window = Tk()
window.title("大豬哥Snake game貪吃")
window.resizable(False, False)
score = 0
direction = 'down'
label = Label(window, text="大豬哥分數:{}".format(score), font=('consolas', 40))
label.pack()
canvas = Canvas(window, bg=BACKGROUND_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()