user_query: Erase all the Costco list items
response_text: It looks like that list is already empty.
user_query: create costco list
response_text: Sure, I made a list called "Costco".
user_query: add diamond ring
response_text: OK. Diamond ring on your list called "Costco". Anything else?
User: Stop tracking my pushup routine.
Parse: Stop_exercise ( activity « pushup » )