title: handle legend in matplotlib?
body: <p>The following is the code:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  
  color_legend = { "c 1 :": "blue", "c 2:":"green", "c 3:":"red"}
  
  f = plt.figure(1)
  ax = f.add_subplot(1,1,1)
  for label in color_legend:
      ax.plot([0],[0],color=color_legend[label],label=label)
  plt.legend(loc="best")
  plt.show()
  </code></pre>
  
  <p>My question is: what exactly are the first two parameters [0] and [0] doing over there? Hope this is not a trivial question. </p>