Can someone please tell me why this code is not adding items to the shopping list? It always has 0 items

#purpose: add itmes to shopping list. Choose index of item on list

shopping_list = []

def show_help():
  print("\nSeparate each item with a comma.")
  print("Type DONE to quit, SHOW to see the current list, and HELP to get this message.")


def show_list():
  count = 1
  for item in shopping_list:
    print("{}: {}".format(count, item))
    count +=1

#code officially begins    
print("Give me a list of things you want to shop for.")
show_help()


while True:
  new_stuff = input("> ")

  if new_stuff == "DONE":
    print("\nHere's your list:")
    show_list()
    break
  elif new_stuff == "HELP":
    show_help()
    continue
  elif new_stuff == "SHOW":
    show_list()
    continue
  else:
    new_list = new_stuff.split(",") #turns string of words separated by comma into list of strings
    index = input("Add this at a certain spot? Press enter for the end of the list, or give me a number. Currently {} items in list.".format(len(shopping_list)))
    if index: #if there is an index
      spot = int(index)-1 
      for item in new_list:
        shopping_list.insert(spot, item.strip())#strip item of an whitespace characters around it
        spot +=1
      else:
        for item in new_list:
          shopping_list.append(item, strip())