title: Set legend symbol opacity with matplotlib?
body: <p>I'm working on a plot with translucent 'x' markers (20% alpha).  How do I make the marker appear at 100% opacity in the legend?</p>
  
  <pre><code>import matplotlib.pyplot as plt
  plt.plot_date( x = xaxis, y = yaxis, marker = 'x', color=[1, 0, 0, .2], label='Data Series' )
  plt.legend(loc=3, mode="expand", numpoints=1, scatterpoints=1 )
  </code></pre>