code: def test_setitem_nested_2(self):
      nested1 = MultiDimensionalMapping([("B", 1)])
      ndmap = MultiDimensionalMapping([("A", nested1)])
      nested2 = MultiDimensionalMapping([("C", 2)])
      nested_clone = nested1.clone()
      nested_clone.update(nested2)
      ndmap.update({"A": nested2})
      self.assertEqual(ndmap["A"].data, nested_clone.data)
  
imports: import numpy
  from holoviews import Dataset, HoloMap
  from holoviews.core import Dimension
  from holoviews.core.ndmapping import MultiDimensionalMapping, NdMapping, UniformNdMapping
  from holoviews.core.overlay import Overlay
  from holoviews.element import Curve
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 30 for calling the NdIndexableMappingTest obj's underlying member method code with example usage: obj.test_setitem_nested_2() without return types