title: how to capture the right click event using getMouse()
body: <p>I am trying to use graphics.py to write a user graphics interface. The problem is that how can I capture the right click event? It seems that the function getMouse() could just returns where the  mouse was left-clicked as a Point object.</p>
  
  <pre><code>    from graphics import *
      def main():
          win = GraphWin("My Circle", 100, 100)
          c = Circle(Point(50,50), 10)
          c.draw(win)
          win.getMouse() # pause for click in window
          win.close()
       main()
  </code></pre>
  
  <p>I want to know how can I capture the right-click event in the window, thanks.</p>