old_contents: """
  Pyramid Pie Chart
  -----------------
  Altair reproduction of http://robslink.com/SAS/democd91/pyramid_pie.htm
  """
  import altair as alt
  import pandas as pd
  
  category = ['Sky', 'Shady side of a pyramid', 'Sunny side of a pyramid']
  color = ["#416D9D", "#674028", "#DEAC58"]
  df = pd.DataFrame({'category': category, 'value': [75, 10, 15]})
  
  alt.Chart(df).mark_arc(outerRadius=80).encode(
      alt.Theta('value:Q', scale=alt.Scale(range=[2.356, 8.639])),
      alt.Color('category:N',
          scale=alt.Scale(domain=category, range=color),
          legend=alt.Legend(title=None, orient='none', legendX=160, legendY=50)),
      order='value:Q'
  ).properties(width=150, height=150).configure_view(strokeOpacity=0)
new_contents: """
  Pyramid Pie Chart
  -----------------
  Altair reproduction of http://robslink.com/SAS/democd91/pyramid_pie.htm
  """
  # category: case studies
  import altair as alt
  import pandas as pd
  
  category = ['Sky', 'Shady side of a pyramid', 'Sunny side of a pyramid']
  color = ["#416D9D", "#674028", "#DEAC58"]
  df = pd.DataFrame({'category': category, 'value': [75, 10, 15]})
  
  alt.Chart(df).mark_arc(outerRadius=80).encode(
      alt.Theta('value:Q', scale=alt.Scale(range=[2.356, 8.639])),
      alt.Color('category:N',
          scale=alt.Scale(domain=category, range=color),
          legend=alt.Legend(title=None, orient='none', legendX=160, legendY=50)),
      order='value:Q'
  ).properties(width=150, height=150).configure_view(strokeOpacity=0)
  
subject: Add pyramid pie chart to case studies