code: public E peek() {
          switch (accessPolicy) {
              case LIFO:
                  return deque.peekLast();
              case FIFO:
                  return deque.peekFirst();
              default:
                  throw new IllegalStateException("Illegal evict policy: " + evictPolicy);
          }
      }
docs: Retrieves, but does not remove the top-most element, i.e., the element that is either the top of the stack or the
  head of the queue, depending on the configured {@link AccessPolicy}.
  
  @return the top-most element of the container