matrix_diagonal         Softening
nearest_neighbor_adaptive
                        Discriminant Adaptive Nearest Neighbor
                        Classification
neighborhood            Neighborhood size
sphere                  Sphering method
tidydann_set_threads    Control the number of threads tidydann uses
tunable.nearest_neighbor_adaptive
                        Declare tunable parameters
update.nearest_neighbor_adaptive
                        Update a model specification
weighted                Weighted between class covariance
