new_contents: """
  Normalized Parallel Coordinates Example
  ----------------------------
  A `Parallel Coordinates <https://en.wikipedia.org/wiki/Parallel_coordinates>`_
  chart is a chart that lets you visualize the individual data points by drawing
  a single line for each of them.
  
  Such a chart can be created in Altair by first transforming the data into a
  suitable representation.
  
  This example shows a modified parallel coordinates chart with the Iris dataset,
  where the y-axis shows the value after min-max rather than the raw value. It's a
  simplified Altair version of `the VegaLite version <https://vega.github.io/vega-lite/examples/parallel_coordinate.html>`_
  """
  # category: other charts
  from altair import datum
  
  source = data.iris()
  
  (alt.Chart(source)
   .transform_window(
       index='count()')
   .transform_fold(
       ['petalLength', 'petalWidth', 'sepalLength', 'sepalWidth'])
   .transform_joinaggregate(
       min='min(value)', max='max(value)',
       groupby=['key'])
   .transform_calculate(minmax_value=(datum.value-datum.min)/(datum.max-datum.min), mid=(datum.min+datum.max)/2)
   .mark_line()
   .encode(
       x='key:N',y='minmax_value:Q',color='species:N',detail='index:N',opacity=alt.value(0.5))
   .properties(width=500)
  )
  
  
subject: add example for normalized parallel coordinates to demo .transform_joinaggregate usage