new_contents: #!/usr/bin/env python
  #
  # To be used as an exercise template for all the rest of the exercises.
  #
  # Style guide to be used: https://google.github.io/styleguide/pyguide.html
  #
  
  def main():
      print "Hello world!"
      return
  
  if __name__ == '__main__':
      main()
  
subject: add ex0 template