code: def test_dimensioned_comparison_unequal_key_dims(self):
      try:
          self.assertEqual(self.dimensioned1, self.dimensioned3)
      except AssertionError as e:
          self.assertEqual(
              str(e), "Dimension names mismatched: key1 != key2"
          )
  
imports: from holoviews.core import Dimension, Dimensioned
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 4 for calling the DimensionedComparisonTestCase obj's underlying member method code with example usage: obj.test_dimensioned_comparison_unequal_key_dims() without return types