title: How can I disable (grey out) a Checkbutton in Tkinter?
body: <p>I can't figure out how to grey out a Tkinter <code>Checkbutton</code>.</p>
  <p>I tried using <code>state=DISABLED</code> but it didn't work and I got an error saying</p>
  <blockquote>
  <p>_tkinter.TclError: bad option &quot;-enable&quot;: must be -column, -columnspan, -in, -ipadx, -ipady, -padx, -pady, -row, -rowspan, or -sticky</p>
  </blockquote>
  <p>How can I temporarily disable a <code>Checkbutton</code>?</p>