code: def test_regular_grid_2d_8():
      ar = np.zeros((20, 40))
      g = regular_grid(ar.shape, 8)
      assert_equal(g, [slice(5.0, None, 10.0), slice(5.0, None, 10.0)])
      ar[g] = 1
      assert_equal(ar.sum(), 8)
  
imports: import numpy
  from skimage.util import regular_grid
  from skimage._shared.testing import assert_equal
label_desc: Use image node_id 2 for calling a global function with example usage: test_regular_grid_2d_8() without return types