code: def test_H11(self):
      h = haralick.Haralick(gray, labels, 0, 1, nlevels=4)
      self.assertAlmostEqual(h.H11()[0], 0.8240, 4)
  
imports: import unittest
  import centrosome.haralick
  import numpy
label_desc: Use image node_id 15 for calling the TestHaralick obj's underlying member method code with example usage: obj.test_H11() without return types