code: def __call__(self, background_data, n_background_samples):
      sampled = self._mock_kmeans(background_data, n_background_samples)
      group_names = [str(i) for i in range(background_data.shape[1])]
  
      if isinstance(background_data, pandas.DataFrame):
          group_names = background_data.columns
  
      return shap_utils.DenseData(sampled, group_names, None)
  
imports: import itertools
  import logging
  import unittest
  from copy import copy
  from itertools import chain
  from unittest.mock import MagicMock
  from typing import Any, List
  import catboost
  import pandas
  import pytest
  import scipy.sparse
  import sklearn
  import shap
  import numpy
  import pandas
  import shap.utils._legacy
  from numpy.testing import assert_allclose, assert_almost_equal
  from scipy.special import expit
  from alibi.api.defaults import DEFAULT_META_KERNEL_SHAP, DEFAULT_DATA_KERNEL_SHAP, DEFAULT_META_TREE_SHAP, DEFAULT_DATA_TREE_SHAP, KERNEL_SHAP_PARAMS, TREE_SHAP_PARAMS
  from alibi.explainers.shap_wrappers import sum_categories, rank_by_importance, KernelExplainerWrapper
  from alibi.explainers.shap_wrappers import KERNEL_SHAP_BACKGROUND_THRESHOLD, TREE_SHAP_BACKGROUND_WARNING_THRESHOLD
  from alibi.explainers.tests.utils import get_random_matrix
  from alibi.tests.utils import assert_message_in_logs, not_raises
  from alibi.utils import DistributedExplainer
label_desc: Use image node_id 3 for calling the KMeansMock obj's underlying member method code with example usage: obj.__call__(background_data, n_background_samples) and returns: shap_utils