My version of shopping list with extra credit.

import os

shopping_list = []

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

def add_to_list(item):
    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(item))
    else:
        position = 0
    try:
        position = abs(int(position))
    except ValueError:
        position = None
    if position is not None:
        shopping_list.insert(position-1, item)
    else:
        shopping_list.append(new_item)
    show_list()

def show_list():
    clear_screen()

    print("Here is your list:")

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

    print("-"*10)

def remove_from_list():
    show_list()
    what_to_remove = input("What would you like to remove?\n >")
    try:
        shopping_list.remove(what_to_remove)
    except ValueError:
        pass
    show_list()

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

show_help()

while True:
    new_item = input("> ")
    if new_item.upper() == "DONE" or new_item.upper() == "QUIT":
        break # This is to break out of the loop
    elif new_item.upper() == "HELP":
        show_help()
        continue #Control flow
    elif new_item.upper == "SHOW":
        show_list()
        continue
    elif new_item.upper() == "REMOVE":
        remove_from_list()
    else:
        add_to_list(new_item)
show_list()