text: Hi,
  I am a newbie here. Trying to learn and deploy my investment through Quantopian. I started with some youtube tutorial videos, and now working through the API docs.
  In the section of pipeline, I tried to run the sample code in the Algorithms. I just copy and paste the attached 'official' code, but the system returned with the Error message: --- Error InvalidSidCount: 0019 Algorithm must reference 1-500 SIDs. Found 0
  So what happened to the code? is it an official documented code? What shall I do?
  Thanks in advance for your help, Allan unwanted rows from output. pipe.set_screen(prices_under_5)
  def before_trading_start(context, data):
  # Access results using the name passed to
  attach_pipeline.
  results = pipeline_output('my_pipeline')
  print results.head(5)