user_query: discard shopping list
response_text: Sorry, I couldn't find any lists with that name.
user_query: shopping list
response_text: Sorry, I looked for Shopping, but couldn't find it. Do you want to see all of your lists?
User: Add to the list of groceries
Parse: Add_item_to_list ( list_label « groceries » list_singular_or_plural « list » )