old_contents: """
  Multi Series Line Chart Layered With Rule Aggregate Lines
  -----------------------
  This example shows how to make a multi series line chart of the daily closing stock prices for AAPL, AMZN, GOOG, IBM, and MSFT between 2000 and 2010.
  """
  
  import altair as alt
  from vega_datasets import data
  
  stocks = data.stocks()
  
  line = alt.Chart(stocks).mark_line().encode(
      x = 'date', 
      y = 'price', 
      color = 'symbol'
  )
  
  rule = alt.Chart(stocks).mark_rule().encode(
      y = alt.Y('average(price)', ),
      color='symbol'
  )
  
  chart = (line + rule)
  #chart.config = {'rule': {'size': 20}}
  #chart.interactive()
  
new_contents: """
  Multi Series Line Chart Layered With Rule Aggregate Lines
  -----------------------
  This example shows how to make a multi series line chart of the daily closing stock prices for AAPL, AMZN, GOOG, IBM, and MSFT between 2000 and 2010.
  """
  
  import altair as alt
  from vega_datasets import data
  
  stocks = data.stocks()
  
  line = alt.Chart(stocks).mark_line().encode(
      x = 'date', 
      y = 'price', 
      color = 'symbol'
  ).interactive()
  
  rule = alt.Chart(stocks).mark_rule().encode(
      y = alt.Y('average(price)', ),
      color='symbol'
  )
  
  chart = (line + rule)
  
subject: clean up based on Jake's comments