old_contents: #!/usr/bin/env python3
  
  shopping_list = []
  
  def show_help():
      print("What should we pick up at the store?")
      print("Enter DONE to stop. Enter HELP for this help. Enter SHOW to see your current list.")
  
  def add_to_list(item):
      shopping_list.append(item)
      print("Added! List has {} items.".format(len(shopping_list)))
  
  def show_list():
      print("Here's your list:")
      for item in shopping_list:
          print(item)
  
  show_help()
  
  while True:
      new_item = input("> ")
      if new_item == 'DONE':
          show_list();
          break
      elif new_item == 'HELP':
          show_help()
          continue
      elif new_item == 'SHOW':
          show_list()
          continue
      add_to_list(new_item)
      continue
  
new_contents: #!/usr/bin/env python3
  
  shoppingList = []
  
  def show_help():
      print("What should we pick up at the store?")
      print("Enter DONE to stop. Enter HELP for this help. Enter SHOW to see your current list.")
  
  def add_to_list(item):
      shoppingList.append(item)
      print("Added! List has {} items.".format(len(shoppingList)))
  
  def show_list():
      print("Here's your list:")
      for item in shoppingList:
          print(item)
  
  show_help()
  
  while True:
      new_item = input("> ")
      if new_item == 'DONE':
          show_list();
          break
      elif new_item == 'HELP':
          show_help()
          continue
      elif new_item == 'SHOW':
          show_list()
          continue
      add_to_list(new_item)
      continue
  
subject: Use CamelCase.