title: Pandas secondary_y: How to place legends outside plot?
body: <p>I am struggling moving the location of legends when I use &quot;secondary_y&quot; in Pandas. The below code gives an example:</p>
  <pre><code>import pandas as pd
  import matplotlib.pyplot as plt
  
  df = pd.DataFrame({'C' : [4,5,6,7], 'S' : [10,20,30,40],'R' : [100,50,-30,-50]})
  fig, ax = plt.subplots()
  df[['C', 'S', 'R']].plot.bar(ax=ax, rot=90,  secondary_y= ['S', 'R'])
  </code></pre>
  <p><a href="https://i.stack.imgur.com/7tyqz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7tyqz.png" alt="enter image description here" /></a></p>
  <p>When not using &quot;secondary_y&quot; the following works</p>
  <pre><code>handles, labels = ax.get_legend_handles_labels()
  fig.legend(handles, labels, loc='lower left', ncol=3,
             bbox_to_anchor=(0.25, -.175))
  </code></pre>
  <p>But the last code above does not work when I use &quot;secondary_y&quot;.</p>
  <p>Does anybody know how to get the legend below the figure?</p>