user_query: make a list called trip
response_text: OK, I made a list called "Trip".
user_query: make a list called travel
response_text: Sure, I made a list called "Travel".
user_query: switch from trip to travel
response_text: Sure. Trip to travel on your list called "Travel". Anything else?
user_query: switch from trip to roadtrip
response_text: Alright. Switch from trip to roadtrip. Anything else?
User: Incorpora pens to the shopping list.
Parse: Add_item_to_list ( items « pens » list_label « shopping » list_singular_or_plural « list » )