user_query: Add an item to the Wedding Registry list.
response_text: What do you want to add?
user_query: welcome mat
response_text: I couldn't find a list called "Wedding Registry." Do you want me to make one?
user_query: That's fine
response_text: Sure, I made a list called "Wedding Registry" and added welcome mat.
User: Withdraw welcome mat and put scented candles.
Parse: Add_item_to_list ( items « scented candles » )