code: def test_ndlayout_overlay_ndlayout_partial(self):
      items = [(0, self.view1), (1, self.view2), (3, self.view2)]
      grid = NdLayout(items, "X")
      items2 = [(0, self.view2), (2, self.view2), (3, self.view3)]
      grid2 = NdLayout(items2, "X")
  
      expected_items = [
          (0, Overlay([self.view1, self.view2])),
          (1, Overlay([self.view2])),
          (2, Overlay([self.view2])),
          (3, Overlay([self.view2, self.view3])),
      ]
      expected = NdLayout(expected_items, "X")
      self.assertEqual(grid * grid2, expected)
  
imports: import numpy
  import pytest
  from holoviews import AdjointLayout, Element, GridSpace, HoloMap, Layout, NdLayout, Overlay
  from holoviews.element import Curve, HLine, Image
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 6 for calling the NdLayoutTest obj's underlying member method code with example usage: obj.test_ndlayout_overlay_ndlayout_partial() without return types