user_query: create last week's to-do list
response_text: Alright, I made a list called "To-Do".
user_query: no, Forget last week's to-do list
response_text: Sorry, I couldn't find any lists with that name.
User: Get tickets to the uh, Yankees game next month.
Parse: BuyEventTickets ( event_performer « Yankees » event_time « next month » )