title: How remove a specific legend label in the Dataframe.plot?
body: <p>I am trying to plot two DataFrame together by 'bar' style and 'line' style respectively, but have trouble when showing the legend only for the bars, excluding the line.</p>
  
  <p>Here are my codes:</p>
  
  <pre><code>import numpy as np
  import pandas as pd
  
  np.random.seed(5)
  df = pd.DataFrame({'2012':np.random.random_sample((4,)),'2014':np.random.random_sample((4,))})
  df.index = ['A','B','C','D']
  sumdf = df.T.apply(np.sum,axis=1)
  ax = df.T.plot.bar(stacked=True)
  sumdf.plot(ax=ax)
  ax.set_xlim([-0.5,1.5])
  ax.set_ylim([0,3])
  ax.legend(loc='upper center',ncol=3,framealpha=0,labelspacing=0,handlelength=4,borderaxespad=0)
  </code></pre>
  
  <p>Annoyingly got this: <a href="https://i.stack.imgur.com/Ojyub.png" rel="noreferrer">Figure</a>, where the line legend is also shown in the legend box. I want to remove it rather than make it invisible.</p>
  
  <p>But I do not find the way.</p>
  
  <p>Thank you!</p>