title: Tkinter - Using multiple key-binds
body: <p>I've made a program which draws an oval on click (mouse click=start point, mouse release= end point) as shown in code below, and I'd like to add if condition: when the <em>shift</em> key is pressed midst drawing, it would equalize the coordinates and therefore as a result, a circle (or perfect oval if you wish) will be drawn.</p>
  
  <pre><code>from tkinter import *
  def draw(event):
      if str(event.type)=='ButtonPress':
          canvas.old_coords=event.x,event.y
      elif str(event.type)=='ButtonRelease':
          x,y=event.x,event.y
          x1,y1=canvas.old_coords
          canvas.create_oval(x,y,x1,y1)
  canvas=Canvas()
  canvas.pack()
  canvas.bind('&lt;B1-Motion&gt;',draw)
  canvas.bind('&lt;ButtonPress-1&gt;',draw)
  canvas.bind('&lt;ButtonRelease-1&gt;',draw)
  </code></pre>
  
  <p>How could I possibly take in account pressed <em>shift</em> and then draw a circle?</p>