user_query: create a grocery list and add celery, tomato, buns, ketchup, mayo to the list
response_text: Sorry, it looks like you already have a list with that name. Do you still want to make a new one?
user_query: yes
response_text: OK, I made a list called "Grocery" and added those three things.
user_query: erase ketchup from grocery list
response_text: I couldn't find ketchup on your list called "Grocery."
user_query: erase buns from the list
response_text: I couldn't find buns.
User: Find street parking near 20th street at 8:00 PM.
Parse: Find_parking ( location « 20th street » parking_type « street » time « 8:00 PM » )