title: Plotly figure hide and display
body: <p>I have a problem with hiding and showing a graph in the Python framework, Dash.
  I define a new graph:</p>
  
  <pre><code>html.Div([
    dcc.Graph(id = 'graph'),
   ],),
  </code></pre>
  
  <p>After I update my trace data with a callback function I return it and it is shown in the graph, but if nothing is selected from my dropdown menu I do</p>
  
  <pre><code>if not input or input == []:
    return {'display': 'none'}
  </code></pre>
  
  <p>so that my graph is not shown, but it doesn't work for some reason. 
  Is there a workaround?</p>
  
  <p>Thank you in advance</p>