code: def prepare_target(self, y):
      return np.vectorize(self.target_mapper.get)(y)
  
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 3 for calling the TabNetClassifier obj's underlying member method code with example usage: obj.prepare_target(y) and returns: np