title: Use onkey() to do multiple functions with Python turtle
body: <p>I'm trying to write a basic turtle drawing game/program and I've been using <code>onkey(function, "key")</code> to have the user input keystrokes. Well I wanted the user to be able to change the width of the pen by either hitting the up key to increase the width by one, or the down key to decrease the width by one. I know I need some kind of loop, but I don't really know where to implement it.</p>