code: public static <E> E last(Iterable<E> iterable) {
          dbc.precondition(iterable != null, "cannot call last with a null iterable");
          return new LastElement<E>().apply(iterable.iterator());
      }
docs: Yields the last element.
  
  @param <E> the iterable element type
  @param iterable the iterable that will be consumed @throw
  IllegalArgumentException if no element is found
  @return the last element