Shopping List Take 3 - Need help debugging

import os

shopping_list = []

def clear_screen():
    os.system("cls" if os.name == "nt" else "clear")

def show_help():
    clear_screen()
    print("What should we pick up at the store?")
    print("""
Enter 'DONE' to stop adding items.
Enter 'HELP' for this help.
Enter 'SHOW' to show the list.
""")


def add_to_list(items):
    show_list()
    if len(shopping_list):
        position = input("Where should I add {}?\n"
                         "Press ENTER to add to the end of the list\n"
                         "> ".format(items))

    else:
        position = 0

    try:
        position = abs(int(position))
    except ValueError:
        position = None
    if position is not None:
        shopping_list.insert(position-1, items)
    else:
        shopping_list.append(new_item)

    show_list()


def show_list():
    clear_screen()

    print("Here's your list:")

    index = 1
    for item in shopping_list:
        print("{}. {}".format(index, items))
        index += 1

    print("-"*10)

show_help()
while True:
    new_item = input(">")

    if new_item.upper() == 'DONE' or new_item.upper() == 'QUIT':
        break
    elif new_item.upper() == 'HELP':
        show_help()
        continue
    elif new_item.upper() == 'SHOW':
        show_list()
        continue
    else:
        add_to_list(new_item)

show_list()

#Error In terminal#

File "list_app.py", line 66, in <module>
    add_to_list(new_item)
  File "list_app.py", line 37, in add_to_list
    show_list()
  File "list_app.py", line 48, in show_list
    print("{}. {}".format(index, items))" 



^^ This is what I get in the terminal when I enter an item on the list. Can someone review my code and help me get back on track pls?