code: def prune_indices(self, transforms=None):
          
          if self.ndim >= 3:
              # In case of a 3D cube, return list of tuples
              # (of row and col pruned indices).
              return self._prune_3d_indices(transforms)
  
          def prune_non_3d_indices(transforms):
              row_margin = self._pruning_base(
                  hs_dims=transforms, axis=self.row_direction_axis
              )
              row_indices = self._margin_pruned_indices(
                  row_margin, self._inserted_dim_inds(transforms, 0), 0
              )
  
              if row_indices.ndim > 1:
                  # In case of MR, we'd have 2D prune indices
                  row_indices = row_indices.all(axis=1)
  
              if self.ndim == 1:
                  return [row_indices]
  
              col_margin = self._pruning_base(
                  hs_dims=transforms, axis=self._col_direction_axis
              )
  
              col_indices = self._margin_pruned_indices(
                  col_margin, self._inserted_dim_inds(transforms, 1), 1
              )
              if col_indices.ndim > 1:
                  # In case of MR, we'd have 2D prune indices
                  col_indices = col_indices.all(axis=0)
  
              return [row_indices, col_indices]
  
          # In case of 1 or 2 D cubes, return a list of
          # row indices (or row and col indices)
          return prune_non_3d_indices(transforms)
docs: Return indices of pruned rows and columns as list.
  
          The return value has one of three possible forms:
  
          * a 1-element list of row indices (in case of 1D cube)
          * 2-element list of row and col indices (in case of 2D cube)
          * n-element list of tuples of 2 elements (if it's 3D cube).
  
          For each case, the 2 elements are the ROW and COL indices of the
          elements that need to be pruned. If it's a 3D cube, these indices are
          calculated "per slice", that is NOT on the 0th dimension (as the 0th
          dimension represents the slices).