code: def test_key_mismatch(self):
      try:
          self.assertEqual(self.map1_1D, self.map2_1D)
          raise AssertionError("Mismatch in map keys not raised.")
      except AssertionError as e:
          self.assertEqual(
              str(e),
              "HoloMaps have different sets of keys."
              " In first, not second [0]. In second, not first: [2].",
          )
  
imports: import numpy
  from holoviews import Image
  from holoviews.core import BoundingBox, Dimension
  from holoviews.core.element import HoloMap
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 4 for calling the RasterMapComparisonTest obj's underlying member method code with example usage: obj.test_key_mismatch() without return types