code: def _unique_indicator(y):
      """
      Not implemented
      """
      raise IndexError(
          f"""Given labels are of size {y.shape} while they should be (n_samples,) \n"""
          + """If attempting multilabel classification, try using TabNetMultiTaskClassification """
          + """or TabNetRegressor"""
      )
  
imports: from collections.abc import Sequence
  from itertools import chain
  from scipy.sparse import issparse
  from scipy.sparse.base import spmatrix
  from scipy.sparse import dok_matrix
  from scipy.sparse import lil_matrix
  import scipy.sparse
  import numpy
  import pandas
label_desc: Use image node_id 4 for calling a global function with example usage: _unique_indicator(y) without return types