user_query: Add toothpaste and hand sanitizer on it
response_text: Alright. Those two things on your list called "Things To Buy". Anything else?
user_query: frozen berries and corn
response_text: Got it. Frozen berries and corn. Anything else?
user_query: add peanut butter and bread
response_text: OK. Frozen berries and corn. Anything else?
User: How's my credit bill last month, actually this month?
Parse: Get_bill ( account_type « credit » billing_date_span « this month » )