code: def test_arr4d():
      test_arr4d = np.zeros((10, 10, 10, 1))
      test_arr4d[:2, :2, :2, 0] = 5  # 8-voxel cluster, high intensity
      test_arr4d[7:, 7:, 7:, 0] = 1  # 27-voxel cluster, low intensity
      test_arr4d[6, 6, 6, 0] = 1  # corner touching second cluster
      test_arr4d[6, 6, 8, 0] = 1  # edge touching second cluster
      test_arr4d[
          3:5, 3:5, 3:5, 0
      ] = -10  # negative cluster, very high intensity
      test_arr4d[5:6, 3:5, 3:5, 0] = 1  # cluster touching negative one
      return test_arr4d
  
imports: import math
  import numpy
  import pytest
  from numpy.testing import assert_array_almost_equal
  from scipy.ndimage import generate_binary_structure
  from nilearn.mass_univariate import _utils
  from nilearn.mass_univariate.tests._testing import get_tvalue_with_alternative_library
label_desc: Use image node_id 2 for calling a global function with example usage: test_arr4d() and returns: test_arr4d