TabError: inconsistent use of tabs and spaces in indentation

shopping_list = []


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


show_help()
while True:
    new_item = input("> ")
        add_to_list(new_item)
    if new_item == 'DONE':
        break
    elif new_item == 'HELP':
        show_help()
        continue
    elif new_item == 'SHOW':
        show_list()

        continue

show_list()