user_query: Set a task to make lunch every weekday
response_text: OK, make lunch every Monday, Tuesday, Wednesday, Thursday, and Friday. At what time?
user_query: I do not want to set a time
response_text: Nothing's been set.
user_query: Set a task to bring notebook to work
response_text: OK, do you want to add time?
user_query: Do not set a time
response_text: Nothing's been set.
user_query: Set a task to water plant every day
response_text: Got it, water plant every day. At what time?
User: How much is the last latest water bill in PDF format?
Parse: Get_bill ( account_type « water » document_format « PDF » )