title: Matplotlib way to annotate bar plots with lines and figures
body: <p><a href="https://i.stack.imgur.com/L4aiM.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/L4aiM.png" alt="enter image description here"></a></p>
  
  <p>I would like to create an annotation to a bar chart that compares the value of the bar to two reference values. An overlay such as shown in the picture, a kind of staff gauge, is possible, but I'm open to more elegant solutions. </p>
  
  <p>The bar chart is generated with the <code>pandas</code> API to <code>matplotlib</code> (e.g. <code>data.plot(kind="bar")</code>), so a plus would be if the solution is playing nicely with that.</p>