title: How to perform an onclick action on button click in python bokeh?
body: <p>I'm new to bokeh and I have aquery regarding button onclick event, the code is provided below:</p>
  
  <pre><code>    x = widgetbox(button)
      show(x)
      fruits = ['Answered', 'Unanswered','Total']
      top1=[1,2,3]
      def callback():
          p = figure(x_range=fruits, plot_height=250, title="sophia bot")
          p.vbar(x=fruits, top=top1, width=0.9)
          p.xgrid.grid_line_color = None
          p.y_range.start = 0
          output_file("abc.html")
          show(p)
      button_one = Button(label="Start", disabled=True, callback=callback)
      show(button_one)
  </code></pre>
  
  <p>but this isnt performing the action, the following code when used alone, does plot the graph, i want the graph to be shown alongisde when i clicke the button.</p>
  
  <pre><code>    fruits = ['Answered', 'Unanswered','Total']
      top1=[1,2,3]
      p = figure(x_range=fruits, plot_height=250, title="sophia bot")
      p.vbar(x=fruits, top=top1, width=0.9)
      p.xgrid.grid_line_color = None
      p.y_range.start = 0
      output_file("abc.html")
      show(p)
  </code></pre>
  
  <p>Thanks</p>