Node<K, V> head;
    Node<K, V> tail;
    int count;

    KeyList(Node<K, V> firstNode) {
      this.head = firstNode;
      this.tail = firstNode;
      firstNode.previousSibling = null;
      firstNode.nextSibling = null;
      this.count = 1;
    }
  }

  private transient @Nullable Node<K, V> head; // the head for all keys

    Node<K, V> head;
    Node<K, V> tail;
    int count;

    KeyList(Node<K, V> firstNode) {
      this.head = firstNode;
      this.tail = firstNode;
      firstNode.previousSibling = null;
      firstNode.nextSibling = null;
      this.count = 1;
    }
  }

  private transient @Nullable Node<K, V> head; // the head for all keys

        if (nodes.isEmpty()) {
            return;
        }

        Element firstNode = nodes.get(0);
        if (!firstNode.getNodeName().equals("para") || !(firstNode.getFirstChild() instanceof Text)) {
            return;
        }

        Text comment = (Text) firstNode.getFirstChild();
        Matcher matcher = ACCESSOR_COMMENT_PATTERN.matcher(comment.getData());

        } else {
          return result;
        }
      }
    };
  }

  /** Returns the first node in the tree that is in range. */
  private @Nullable AvlNode<E> firstNode() {
    AvlNode<E> root = rootReference.get();
    if (root == null) {
      return null;
    }
    AvlNode<E> node;
    if (range.hasLowerBound()) {