title: How to add y-axis label to df.boxplot
body: <p>I generate a boxplot out of a dataframe with:</p>
  
  <pre><code>bplot = df.boxplot(
      column=column_name,
      by=list1,
      fontsize=8,
      layout=(2,1),
      rot=90,
      figsize=(25,20)
  )
  </code></pre>
  
  <p>Where <code>df</code> is my dataframe, <code>column_name</code> is my wanted column and <code>list1</code> is the list to use for groupby?</p>
  
  <p>I want to label my y-axis with a string. Tried this:</p>
  
  <pre><code>plt.ylabel('ylabel')
  </code></pre>
  
  <p>but does not work.</p>