Get tkinter.tclerror when closing python turtle before it finished it's draw

Paint the turtle on a Canvas object from which you can have access to the Tkinter root.Capture the WM_DELETE_WINDOW event of the root. When the event is captured, del the turtle object so that it can't keep trying to draw. The thread controlling the turtle events will throw a NameError because the turtle has been deleted. Catch the NameError exception and ignore it.

Here's code to do this. I tested it; it works & doesn't thrown any error:

import turtleimport Tkinterimport sysimport easygui as egdef isNum(s):    try:        int(s)        return True    except ValueError:        return Falserun = Truewhile run:    msg         = "Input"    title       = "Koch snowflake"    fieldNames  = ["Length","Depth"]    fieldValues = []  # we start with blanks for the values    fieldValues = eg.multenterbox(msg,title, fieldNames)    a=0    iterations=0# make sure that none of the fields was left blank    while 1:  # do forever, until we find acceptable values and break out        if fieldValues == None:             break        errmsg = ""        # look for errors in the returned values        for i in range(len(fieldNames)):            if fieldValues[i].strip() == "":                errmsg = errmsg + ('"%s" must be filled.\n\n' % fieldNames[i])            elif not (isNum(fieldValues[i].strip())):                errmsg = errmsg + ('"%s"  requires a number.\n\n' % fieldNames[i])        if (isNum(fieldValues[1])):            if float(fieldValues[1].strip()) > 13:                errmsg = errmsg + ('Depth cannot be more than 13!')         if errmsg == "":             break # no problems found        else:            # show the box again, with the errmsg as the message                fieldValues = eg.multenterbox(errmsg, title, fieldNames, fieldValues)    #a=float(input("Length: "))    if not fieldValues == None:        if isNum(fieldValues[0]) and isNum(fieldValues[1]):            a=float(fieldValues[0])            iterations=int(fieldValues[1])    else:        sys.exit(0)    root = Tkinter.Tk()    cv = turtle.Canvas(root, width=200, height=200)    cv.pack()    screen = turtle.TurtleScreen(cv)    screen.bgcolor("black")    myturtle = turtle.RawTurtle(screen)    def lastAction():        global myturtle        del myturtle        root.destroy()    root.protocol('WM_DELETE_WINDOW', lastAction)    try:#turtle settings        screen.bgcolor("black")        myturtle.reset()        myturtle.up()         myturtle.setpos(-a*1.5 ,a)        myturtle.down()        turtle.delay(0)        myturtle.speed(0)        myturtle.pencolor("white")        koch_flake = "EJEJE"        for i in range(iterations):            koch_flake = koch_flake.replace("E","EBEJEBE\n")        myturtle.down()        for move in koch_flake:            if move == "E":                myturtle.forward(a / (3 ** (iterations - 1)))            elif move == "B":                myturtle.left(60)            elif move == "J":                myturtle.right(120)        myturtle.hideturtle()    except NameError:        pass    image   = "KochSnowflake.gif"    msg = "Run it again?"    title = "Please Confirm"    if eg.ynbox(msg, title,('Yes', 'No'),image):     # show a Continue/Cancel dialog        run = True    else:  # user chose Cancel        sys.exit(0)