code: def test_overlay_comparison_unequal_data(self):
      t1 = self.el1 * self.el2
      t2 = self.el1 * self.el3
      try:
          self.assertEqual(t1, t2)
      except AssertionError as e:
          self.assertEqual(str(e), "'data2' != 'data3'")
  
file_path: holoviews/holoviews/tests/element/test_comparisoncomposite.py
imports: from holoviews import Element
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 9 for calling the CompositeComparisonTestCase obj's underlying member method code with example usage: obj.test_overlay_comparison_unequal_data() without return types