old_contents: #!/usr/bin/python
  # -*- coding: utf-8 -*-
  
  
  def hello():
  	"""this is a test function"""
  	print 'hello world'
  
  
  if __name__ == '__main__':
  	hello()
  
  
new_contents: #!/usr/bin/python
  # -*- coding: utf-8 -*-
  
  
  def hello():
  	"""this is a test function"""
  	print 'hello world'
  
  
  def world():
  	print 'world'
  
  
  if __name__ == '__main__':
  	hello()
  
  
subject: add new feature