user_query: new tires, add to list
response_text: What do you want to add?
user_query: new tire
response_text: I couldn't find a list called "Tires." Do you want me to make one?
user_query: walmart list addition
response_text: OK. Which list do you want to add to?
User: Retrieve the July invoice for AEP electric.
Parse: Get_bill ( account_provider « AEP » account_type « electric » billing_date_span « July » )