user_query: Add Speaker, headset and camera to my Shopping list.
response_text: Sure, I added those two things.
user_query: Remove speaker from the list.
response_text: I couldn't find speaker.
user_query: Remove headset from the list.
response_text: I couldn't find headset.
user_query: Remove speaker from Shopping list.
response_text: I couldn't find speaker on your list called "Shopping."
User: See if I can buy Elton John tickets off ScoreBig.
Parse: BuyEventTickets ( event_performer « Elton John » provider « ScoreBig » )