Load into the specified item a reference to the element in this list with the specified key found by searching the list from the back (in descending order of key value). If multiple elements having key are in the container, load item with the last matching element. key are present, find the last one. Return 0 on success, and a non-zero value (with no effect on item) if no such element exists. If there are multiple elements in the list with the key, it is undefined which one is returned.