     /// ```
     ///
     @inline(__always)
-    @discardableResult
     fileprivate func leftRotate(node a: NodeType) -> NodeType? {
 
         var newRoot: NodeType? = nil

    /// ```
    ///
    @inline(__always)
    @discardableResult
    fileprivate func rightLeftRotate(node a: NodeType) -> NodeType? {

        var newRoot: NodeType? = nil

    /// ```
    ///
    @inline(__always)
    fileprivate func rightRotate(node c: NodeType) -> NodeType? {

        var newRoot: NodeType? = nil
