docstr: Test HE stain extraction on an image that comprises
  only transparent pixels - pixels with absorbance below the
  beta absorbance threshold. A ValueError should be raised,
  since once the transparent pixels are removed, there are no
  remaining pixels to compute eigenvectors.
docstr_tok: ["Test","HE","stain","extraction","on","an","image","that","comprises","only","transparent","pixels","-","pixels","with","absorbance","below","the","beta","absorbance","threshold",".","A","ValueError","should","be","raised",",","since","once","the","transparent","pixels","are","removed",",","there","are","no","remaining","pixels","to","compute","eigenvectors","."]
code: def test_transparent_image(self, image):
      """
      Test HE stain extraction on an image that comprises
      only transparent pixels - pixels with absorbance below the
      beta absorbance threshold. A ValueError should be raised,
      since once the transparent pixels are removed, there are no
      remaining pixels to compute eigenvectors.
      """
      if image is None:
          with self.assertRaises(TypeError):
              ExtractHEStains()(image)
      else:
          with self.assertRaises(ValueError):
              ExtractHEStains()(image)
  
file_path: MONAI/tests/test_pathology_he_stain.py
imports: from __future__ import annotations
  import unittest
  import numpy
  from parameterized import parameterized
  from monai.apps.pathology.transforms import ExtractHEStains, NormalizeHEStains
label_desc: Use image node_id 1 for calling the TestExtractHEStains obj's underlying member method code with example usage: obj.test_transparent_image(image) without return types