title: TypeError: violinplot() got an unexpected keyword argument 'quantiles'
body: <p>I'm trying to make a violin plot that shows the 0.25 and 0.75 quantiles, but keep getting a TypeError, despite the documentation suggesting this is a valid keyword.</p>
  <p>Here is my code:</p>
  <pre><code>grid = plt.GridSpec(1, 1, wspace=0.15, hspace=0.1)
  
  plotplag = fig.add_subplot(grid[0,0])
  
  plotplag.set_xticks([1,2,3,4,5,6,7,8])
  plotplag.violinplot([S95BCore_an, S95BRim_an, S98Core_an, S98Rim_an, VHCoreLZ_an, VHRimLZ_an, VHCoreUZ_an, VHRimUZ_an], showmeans=True, quantiles=[[0.75], [0.25]])
  plotplag.set_xticklabels(['S95B Core', 'S95B Rim', 'S98 Core', 'S98 Rim', 'MS LZ Core', 'MS LZ Rim', 'MS UZ Core', 'MS UZ Rim'])
  
  plotplag.set_ylabel('An# (mol. %)', fontsize=16)
  </code></pre>