code: def stack_batches(self, list_y_true, list_y_score):
      y_true = np.vstack(list_y_true)
      y_score = np.vstack(list_y_score)
      return y_true, y_score
  
imports: import torch
  import numpy
  from scipy.special import softmax
  from pytorch_tabnet.utils import SparsePredictDataset, PredictDataset, filter_weights
  from pytorch_tabnet.abstract_model import TabModel
  from pytorch_tabnet.multiclass_utils import infer_output_dim, check_output_dim
  from torch.utils.data import DataLoader
  import scipy
label_desc: Use image node_id 6 for calling the TabNetRegressor obj's underlying member method code with example usage: obj.stack_batches(list_y_true, list_y_score) and returns: y_true,  y_score