title: How to change Tkinter Button state from disabled to normal?
body: <p>I need to change the state of a <code>Button</code> from <code>DISABLED</code> to <code>NORMAL</code> when some event occurs.</p>
  <p>The button is currently created in the DISABLED state using the following code:</p>
  <pre class="lang-py prettyprint-override"><code>self.x = Button(self.dialog, text=&quot;Download&quot;, state=DISABLED,
                  command=self.download).pack(side=LEFT)
  </code></pre>
  <p>How can I change the state to <code>NORMAL</code>?</p>