How Many In Stock

An Inventory keeps a dict attribute stock from item name to quantity, and add is already written. Write the body of quantity so it returns the stored amount for item, or 0 when the item is not a key at all; reading a missing key directly would crash. Do NOT write a main block or any top-level test code; the tests construct the class. Input: one line, an item name, which the tests read and pass to quantity on an inventory holding 3 apples and 5 pears before printing the number your method returns.