old_contents: #!/usr/bin/env python
  
  # -*- coding: utf-8 -*-
  
  print("Hello World")
  
new_contents: #!/usr/bin/env python
  
  import sys
  
  # -*- coding: utf-8 -*-
  
  
  def greet(name):
      print('Hello, {0}!'.format(name))
  
  
  if len(sys.argv) > 1:
      name = sys.argv[1]
      greet(name)
  else:
      greet('world')
  
subject: update sample