text: """ This example uses the Iris data to demonstrate the specification of
  combined variables using chart operations.
  
  This specific instance uses a blend, which stacks columns, and renames
  the combined column. This can be used where the column itself is a type
  of categorical variable. Here, length and width are derived from the
  petal and sepal measurements.
  """
  
  from bokeh.charts import Scatter, output_file, show
  from bokeh.charts.operations import blend
  from bokeh.sampledata.iris import flowers as data
  
  scatter = Scatter(data,
                    x=blend('petal_length', 'sepal_length', name='length'),
                    y=blend('petal_width', 'sepal_width', name='width'),
                    color='species',
                    title='x=petal_length+sepal_length, y=petal_width+sepal_width, color=species',
                    legend='top_right')
  
  output_file("iris_blend.html", title="iris_blend.py example")
  
  show(scatter)
  