code: def test_dilate_erode_symmetry(self):
      for s in self.footprints:
          c = gray.erosion(self.black_pixel, s)
          d = gray.dilation(self.white_pixel, s)
          assert np.all(c == (255 - d))
  
imports: import inspect
  import numpy
  import pytest
  from scipy import ndimage
  from numpy.testing import assert_allclose, assert_array_equal, assert_equal
  from skimage import color, data, transform
  from skimage._shared._warnings import expected_warnings
  from skimage._shared.testing import fetch
  from skimage.morphology import gray, footprints
  from skimage.util import img_as_uint, img_as_ubyte
label_desc: Use image node_id 2 for calling the TestEccentricStructuringElements obj's underlying member method code with example usage: obj.test_dilate_erode_symmetry() without return types