code: def test_collate_layout_overlay(self):
      layout = self.nested_overlay + self.nested_overlay
      collated = Collator(kdims=["alpha", "beta"])
      for k, v in self.nested_overlay.items():
          collated[k] = v + v
      collated = collated()
      self.assertEqual(collated.dimensions(), layout.dimensions())
  
file_path: holoviews/holoviews/tests/core/test_collation.py
imports: import itertools
  import numpy
  from holoviews.core import Collator, GridSpace, HoloMap, NdOverlay, Overlay
  from holoviews.element import Curve
  from holoviews.element.comparison import ComparisonTestCase
label_desc: Use image node_id 6 for calling the TestCollation obj's underlying member method code with example usage: obj.test_collate_layout_overlay() without return types