code: def test_idxmapping_groupby_unsorted(self):
      data = [(("B", 2), 1), (("C", 2), 2), (("A", 1), 3)]
      grouped = NdMapping(data, sort=False, kdims=["X", "Y"]).groupby(
          "Y"
      )
      self.assertEqual(grouped.keys(), [2, 1])
      self.assertEqual(grouped.values()[0].keys(), ["B", "C"])
      self.assertEqual(grouped.last.keys(), ["A"])
  
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 22 for calling the NdIndexableMappingTest obj's underlying member method code with example usage: obj.test_idxmapping_groupby_unsorted() without return types