private Node RightLeftRotate(Node grandParentNode) {
    grandParentNode.Right = RightRotate(grandParentNode.Right);
    return LeftRotate(grandParentNode);
  }

private Node LeftRightRotate(Node grandParentNode) {
    grandParentNode.Left = LeftRotate(grandParentNode.Left);
    return RightRotate(grandParentNode);
}