new_contents: """
  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, but requires some data preprocessing
  to transform the data into a suitable representation.
  This example shows a parallel coordinates chart with the Iris dataset.
  """
  # category: other charts
  
  import altair as alt
  from vega_datasets import data
  
  iris = data.iris()
  iris_transformed = iris.reset_index().melt(['species', 'index'])
  
  alt.Chart(iris_transformed).mark_line().encode(
      x='variable:N',
      y='value:Q',
      color='species:N',
      detail='index:N',
      opacity=alt.value(0.5)
  ).properties(width=500)
  
subject: add parallel coordinates example