title: Unable to execute subplot command for multiple graphs in matplotlib pyplot
body: <p>this is my dataframe(named census):</p>
  <pre><code>    Ethnicity   USA All CA All  USA Children    CA Children
  0   Black       0.12    0.05            0.14    0.05
  1   Hispanic    0.18    0.38            0.24    0.50
  2   White       0.62    0.39            0.52    0.29
  3   Other       0.08    0.18            0.10    0.16
  </code></pre>
  <p>im trying to show parallel plots, but cant seem to find where i am going wrong
  this is my code:</p>
  <pre><code>error im facing:
  ---------------------------------------------------------------------------
  ValueError                                Traceback (most recent call last)
  &lt;ipython-input-32-c9aa8709606a&gt; in &lt;module&gt;
  ----&gt; 1 fig, (ax1,ax2,ax3,ax4) = plt.subplots(nrows = 2, ncols = 2)
        2 plt.tight_layout()
        3 ax1 = census[['USA All','CA All','Ethnicity']]
        4 ax1.plot.barh()
        5 
  
  ValueError: not enough values to unpack (expected 4, got 2)
  fig, (ax1,ax2,ax3,ax4) = plt.subplots(nrows = 2, ncols = 2)
  plt.tight_layout()
  ax1 = census[['USA All','CA All','Ethnicity']]
  ax1.plot.barh()
  
  ax2 = census[['USA All','CA Children','Ethnicity']]
  ax2.plot.barh()
  
  ax3 = census[['USA Children','CA Children','Ethnicity']]
  ax3.plot.barh()
  
  ax4 = census[['USA All','USA Children','Ethnicity']]
  ax4.plot.barh()
  
  plt.tight_layout()
  </code></pre>