code: public void insertAsPrevious(BasicDoubleLinkedNode<V> node) {
  
      if (this.previous != null) {
        this.previous.setNext(node);
        node.previous = this.previous;
      }
      node.setNext(this);
      this.previous = node;
    }
docs: This method inserts the given {@code node} into the list immediately before the position represented by this node.
  
  @param node is the {@link BasicDoubleLinkedNode node} to add.