Python Turtle Space Invaders 子弹没有击中入侵者

Question

总的来说，我对乌龟和 python 很陌生，所以如果我的代码看起来很乱，我深表歉意。我目前正在编写太空入侵者的乌龟版本，我不明白为什么我的入侵者在击中乌龟时没有死。该代码似乎与我能找到的所有其他太空入侵者海龟程序相同。任何帮助将不胜感激。import turtleimport randomimport math#### Player ####player1 = turtle.Turtle()player1.shape("arrow")player1.color("white")player1.speed(0)player1.penup()player1.setheading(90)player1.setposition(0, -175)player1.speed(4)def move_right():    x = player1.xcor()    x += playerspeed    if x > 210:        x = 210    player1.setx(x)def move_left():    x = player1.xcor()    x -= playerspeed    if x < -210:        x = -210    player1.setx(x)bulletlist = []def fire():    if len(bulletlist) < 5:        bulletlist.append(Bullet())#### Window ####win = turtle.Screen()win.bgcolor("black")win.tracer(2)border_pen = turtle.Turtle()border_pen.speed(0)border_pen.color("white")border_pen.penup()border_pen.setposition(-225, -225)border_pen.pensize(3)border_pen.pendown()for side in range(4):    border_pen.fd(450)    border_pen.lt(90)border_pen.hideturtle()### Invader ###class Invader(turtle.Turtle):    def __init__(self, xcor, ycor):        turtle.Turtle.__init__(self)        self.color("red")        self.shape("turtle")        self.penup()        self.speed(0)        self.setposition(xcor, ycor)        self.setheading(270)        self.speed(1)        self.hit = 0### Bullet ###bulletstate = 1class Bullet(turtle.Turtle):    def __init__(self):        turtle.Turtle.__init__(self)        self.color("yellow")        self.shape("arrow")        self.shapesize(.5, 1)        self.penup()        self.speed(0)        self.setheading(90)        self.hideturtle()        self.bulletspeed = 20fire()def bullet_movement():    global firedb    firedb = bulletlist[-1]    firedb.speed(0)    ybul = firedb.ycor()    ybul += 10    firedb.sety(ybul)    if ybul > 195:        firedb.hideturtle()