title: matplotlib histograms and labels
body: <p>I am plotting a histogram with two sets of data and want to include a key. I have found an example that uses the label command, but when I use this it doesn't work. The histogram appears correctly, but there is no key. My code is.</p>
  
  <pre><code>H1 = &lt;some data&gt;
  S1 = &lt;some other data&gt;
  
  hist([H1,S1], bins=25, range=(10,30), align=('mid'), color=['green', 'orange'], label=['Actual H band', 'Actual IRAC2 band'])
  title("Actual observed magnitudes of sources in H and IRAC2")
  xlabel("Magnitude")
  ylabel("Frequency")
  
  show()
  </code></pre>
  
  <p>Any suggestions?</p>