Refresh old question - Rectangle with 2 mouse clicks

[pythonoob]

I have been assigned the same homework task as a previous poster (Fo.katia): create a program that draws a rectangle with two mouse clicks. I had modified the code in my textbook as the previous poster did with the same results. I saw a reply to the other post that said "There is a line missing somewhere, such as 1. win = GraphWin("My Rectangle", 300, 300)". I tried adding this to my code

win = GraphWin("Draw a Rectangle", 100, 100)

but I still only got a line. I can see the logic in this statement but cannot figure out how to actually make this work. Here is my code:

# rectangle.pyw
from graphics import *

def main():
    win = GraphWin("Draw a Rectangle", 100, 100)
    win.setCoords(0.0, 0.0, 10.0, 10.0)
    message = Text(Point(5, 0.5), "Click on two points")
    message.draw(win)

    # Get and draw a rectangle
    p1 = win.getMouse()
    p1.draw(win)
    p2 = win.getMouse()
    p2.draw(win)
    p3 = win.getMouse()
    p3.draw(win)
    p4 = win.getMouse()
    p4.draw(win)

    # Use Polygon object to draw a rectangle
    rectangle = Polygon(p1,p2,p3,p4)
    rectangle.setFill("purple")
    rectangle.setOutline("black")
    rectangle.draw(win)

    # Wait for another click to exit
    message.setText("Click anywhere to quit.")
    win.getMouse()

main()

Any assistance with this would be greatly appreciated.