user_query: add an item to a list
response_text: Got it. Which list do you want to add to?
user_query: grocery
response_text: What do you want to add?
user_query: scratch that add an item to my traveling list
response_text: Which item?
User: How much was my T-Mobile bill from last month.
Parse: Get_bill ( account_provider « T-Mobile » billing_date_span « last month » )