code: def test_blob_doh_no_peaks():
      # Testing no peaks
      img_empty = np.zeros((100, 100))
      assert blob_doh(img_empty).size == 0
  
imports: import math
  import numpy
  import pytest
  from numpy.testing import assert_almost_equal
  from skimage import feature
  from skimage.draw import disk
  from skimage.draw.draw3d import ellipsoid
  from skimage.feature import blob_dog, blob_doh, blob_log
  from skimage.feature.blob import _blob_overlap
label_desc: Use image node_id 13 for calling a global function with example usage: test_blob_doh_no_peaks() without return types