user_query: Add Blade to the list.
response_text: Alright. Which list do you want to add to?
user_query: Music
response_text: OK. Which list do you want to add to?
user_query: Music
response_text: OK. Which list do you want to add to?
user_query: Music list
response_text: What do you want to add?
user_query: Blade
response_text: OK, I added Blade.
User: How much is the power bill for June?
Parse: Get_bill ( account_type « power » billing_date_span « June » )