Python程序 Catmouseme

import turtleimport timeboxsize=200caught=Falsescore=0#functions that are called on keypressesdef up():    mouse.forward(10)    checkbound()def left():    mouse.left(45)def right():    mouse.right(45)def down():    mouse.backward(10)    checkbound()def quitTurtles():    window.bye()#stop the mouse from leaving windowdef checkbound():    global boxsize    if mouse.xcor() > boxsize:        mouse.goto(boxsize,mouse.ycor())    if mouse.xcor() < -boxsize:        mouse.goto(-boxsize,mouse.ycor())    if mouse.ycor() > boxsize:        mouse.goto(mouse.xcor(),boxsize)    if mouse.ycor() < -boxsize:        mouse.goto(mouse.xcor(),-boxsize)#setup screenwindow = turtle.Screen()mouse = turtle.Turtle()cat= turtle.Turtle()me=turtle.Turtle()mouse.goto(100,100)me.goto(-100,-100)#add key listenerswindow.onkeypress(up,"Up")window.onkeypress(left,"Left")window.onkeypress(right,"Right")window.onkeypress(down,"Down")window.onkeypress(quitTurtles, "Escape")difficulty=window.numinput("Difficulty",    "Enter a difficulty from 1 - 5",    minval=1, maxval=5)window.listen()#mainloop#note how it changes with difficultywhile not caught:    cat.setheading(cat.towards(mouse))    cat.forward(8+difficulty)    me.setheading(me.towards(cat))    me.forward(10+difficulty)    score = score+1    if cat.distance(mouse)<5:        caught=True    elif me.distance(cat)<5:        caught=True    time.sleep(0.2-(0.01*difficulty))window.textinput("GG","Welldone. You scored:"        + str(score*difficulty))window.bye()