title: Bokeh: AttributeError: 'DataFrame' object has no attribute 'tolist'
body: <p>I am new to pandas and bokeh and I am trying to create a scatter plot from a pandas dataframe. However, I keep getting the following error:     </p>
  
  <pre><code>new_data[colname] = df[colname].tolist()
  AttributeError: 'DataFrame' object has no attribute 'tolist' 
  </code></pre>
  
  <p>Using the dummy data from bokeh (from bokeh.sampledata.iris import flowers as data) the scatter works fine.  </p>
  
  <pre><code>   type   tsneX      tsneY      +50.000 columns
  0  A      53.828863  20.740931  
  1  B      57.816909  18.478468  
  2  A      55.913429  22.948167  
  3  C      56.603005  15.738954 
  
  
  scatter = Scatter(df, x='tsneX', y='tsneY',
                    color='type', marker='type',
                    title='t-sne',
                    legend=True)
  </code></pre>
  
  <p>Edit:
  I'm not using the tolist(), but the Scatter() of Bokeh does and produces the error below.</p>