user_query: Also bacon
response_text: OK. Bacon on your list called "shopping". Anything else?
user_query: Eggs
response_text: Sure, I added Eggs.
user_query: Could I add some items to my shopping list
response_text: What do you want to add?
User: I want to see my cellphone bill from last week, uh, I mean, last month.
Parse: Get_bill ( account_type « cellphone » billing_date_span « last month » )