title: jupyter ipywidgets doesn't show function return value
body: <p>I used the most simply example :</p>
  
  <pre><code>from ipywidgets import interact, widgets
  from IPython.display import display
  
  
  # this is a sample function
  def myfunc(x):
      display(x*2) # I add this for testing
      print(x*2)  # I add this for testing
      return x*2
  
  interact(myfunc,x=widgets.IntSlider(min=-10,max=10,value=0))
  </code></pre>
  
  <p>while sliding slider, no output .</p>
  
  <p><a href="https://i.stack.imgur.com/puemN.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/puemN.png" alt="enter image description here"></a></p>
  
  <p>But same example in <a href="http://queirozf.com/entries/interactive-controls-for-jupyter-notebooks-python-examples" rel="nofollow noreferrer">here</a> does show output :
   <a href="https://i.stack.imgur.com/rbW1i.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rbW1i.gif" alt="enter image description here"></a></p>
  
  <p>How do I fix jupyter to show the output ?</p>