title: How do I show legend for different colors in bokeh scatter plot?
body: <p>This is my <a href="https://cdn.rawgit.com/eldor4do/smit-results/master/cgpa.html" rel="nofollow">plot</a>.<br>
  I need to show the legend for the different colors used.<br>
  How do I do that?</p>
  
  <p>My code for the plot:</p>
  
  <pre><code>def mscatter(p, x, y, c,typestr,source):
      p.scatter(x, y, marker=typestr,
              line_color="#6666ee", fill_color=c, fill_alpha=0.5, size=y*1.5,source = source)
  
  p = figure(title="CGPA of 4th year students",tools=[hover])
  mscatter(p, xdata, ydata, colors,"circle",source)
  show(p)
  </code></pre>