title: Vertical lines to separate boxplot groups in python
body: <p>I would like to draw additional vertical lines that will separate grouped boxplots like in the right-hand picture. The left-hand picture is the original picture (source: <a href="https://www.originlab.com/doc/Origin-Help/DoubleY-Box-Chart" rel="nofollow noreferrer">https://www.originlab.com/doc/Origin-Help/DoubleY-Box-Chart</a>). I would appreciate for help how to do that by using matplotlib or seaborn package. Thank you and best regards.</p>
  
  <p><a href="https://i.stack.imgur.com/FAwSv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FAwSv.png" alt="enter image description here"></a></p>
  
  <p>The simple code I am using to create example boxplot:</p>
  
  <pre><code>fig, ax = plt.subplots(1, sharex=False, sharey=False, gridspec_kw={'hspace': 0}, figsize=(10, 5))
  bill = sns.load_dataset("tips")
  sns.boxplot(x="day", y="total_bill", hue="sex", data=bill, palette="PRGn")
  </code></pre>