code: def test_marching_cubes_isotropic():
      ellipsoid_isotropic = ellipsoid(6, 10, 16, levelset=True)
      _, surf = ellipsoid_stats(6, 10, 16)
  
      # Classic
      verts, faces = marching_cubes(
          ellipsoid_isotropic, 0.0, method="lorensen"
      )[:2]
      surf_calc = mesh_surface_area(verts, faces)
      # Test within 1% tolerance for isotropic. Will always underestimate.
      assert surf > surf_calc and surf_calc > surf * 0.99
  
      # Lewiner
      verts, faces = marching_cubes(ellipsoid_isotropic, 0.0)[:2]
      surf_calc = mesh_surface_area(verts, faces)
      # Test within 1% tolerance for isotropic. Will always underestimate.
      assert surf > surf_calc and surf_calc > surf * 0.99
  
file_path: scikit-image/skimage/measure/tests/test_marching_cubes.py
imports: import numpy
  import pytest
  from numpy.testing import assert_allclose
  from skimage.draw import ellipsoid, ellipsoid_stats
  from skimage.measure import marching_cubes, mesh_surface_area
label_desc: Use image node_id 1 for calling a global function with example usage: test_marching_cubes_isotropic() without return types