title: Is there a way to label the mean and median in matplotlib boxplot legend?
body: <p>I have the following box plot which plots some values with different mean and median values for each box; I am wondering if there is any way to label them so that they appear on the graph legend (because the current box plot plots an orange line for the median and a blue dot for the mean and it is not so clear which is which)? Also is there a way to make one legend for these subplots, instead of having a legend for each one, since they are essentially the same objects just different data?</p>
  
  <p>Here's a code example for one of the subplots, the other subplots are the same but have different data:</p>
  
  <pre><code>fig = plt.figure()
  xlim = (4, 24)
  ylim = (0, 3700)
  
  plt.subplot(1,5,5)
  x_5_diff = {5: [200, 200, 291, 200, 291, 200, 291, 200, 291, 200, 291, 200, 291, 200, 291],
   7: [161, 161, 179, 161, 179, 161, 179, 161, 179, 161, 179, 161, 179, 161, 179],
   9: [205, 205, 109, 205, 109, 205, 109, 205, 109, 205, 109, 205, 109, 205, 109],
   11: [169, 169, 95, 169, 95, 169, 95, 169, 95, 169, 95, 169, 95, 169, 95],
   13: [43, 43, 70, 43, 70, 43, 70, 43, 70, 43, 70, 43, 70, 43, 70],
   15: [33, 33, 39, 33, 39, 33, 39, 33, 39, 33, 39, 33, 39, 33, 39],
   17: [23, 23, 126, 23, 126, 23, 126, 23, 126, 23, 126, 23, 126, 23, 126],
   19: [17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17],
   21: [15, 15, 120, 15, 120, 15, 120, 15, 120, 15, 120, 15, 120, 15, 120],
   23: [63, 63, 25, 63, 25, 63, 25, 63, 25, 63, 25, 63, 25, 63, 25]}
  
  keys = sorted(x_5_diff)
  plt.boxplot([x_5_diff[k] for k in keys], positions=keys)  # box-and-whisker plot
  plt.hlines(y = 1600, colors= 'r', xmin = 5, xmax = 23, label = "Level 1 Completed")
  plt.title("x = 5 enemies")
  plt.ylim(0,3700)
  plt.plot(keys, [sum(x_5_diff[k]) / len(x_5_diff[k]) for k in keys], '-o')
  
  
  plt.legend()
  plt.show()
  </code></pre>
  
  <p>Any help would be appreciated.</p>