title: multiple commands on button press
body: <p>How would I change this code so that I can also have it start a function called <code>Drop_down_menu()</code></p>
  
  <pre><code>done_btn = Button(root, text = "Done", command = lambda: root.destroy())       
  done_btn.pack()
  </code></pre>
  
  <p>I have looked at previous articles which say use a function and have the operations there but then it says root is not defined.</p>