Python ошибка вылет

 import turtle 
import pygame 
def draw_cake(): 
    screen = turtle.Screen() 
    screen.bgcolor("white") 
    cake_turtle = turtle.Turtle() 
    cake_turtle.shape("circle") 
    cake_turtle.color("brown") 
    cake_turtle.penup() 
    cake_turtle.goto(0, -100) 
    cake_turtle.pendown() 
    cake_turtle.begin_fill() 
    cake_turtle.circle(100) 
    cake_turtle.end_fill() 
 
# Пишем "С днем рождения!" 
def write_birthday_message(): 
    birthday_turtle = turtle.Turtle() 
    birthday_turtle.penup() 
    birthday_turtle.goto(-50, 0) 
    birthday_turtle.color("black") 
    birthday_turtle.write("С днем рождения!", font=("Arial", 16, "bold")) 
def song(): 
  pygame.mixer.init() 
  sound = pygame.mixer.Sound("sound.wav") 
  sound.play() 
  pygame.time.wait(int(sound.get_length() * 1000)) 
  print("hi")