user_query: Add Sting to my list.
response_text: Alright. Which list do you want to add to?
user_query: Music
response_text: Got it. Which list do you want to add to?
user_query: Music list
response_text: What do you want to add?
user_query: Sting
response_text: What do you want to add?
User: Let me see a PDF document document of my Comcast bill for the last billing cycle.
Parse: Get_bill ( account_provider « Comcast » billing_cycle « last billing cycle » document_format « PDF » )