code: def test_multi_polygon_roundtrip(self):
      xs = [1, 2, 3, np.nan, 6, 7, 3]
      ys = [2, 0, 7, np.nan, 7, 5, 2]
      holes = [
          [
              [(1.5, 2), (2, 3), (1.6, 1.6)],
              [(2.1, 4.5), (2.5, 5), (2.3, 3.5)],
          ],
          [],
      ]
      poly = Polygons(
          [
              {"x": xs, "y": ys, "holes": holes, "z": 1},
              {"x": xs[::-1], "y": ys[::-1], "z": 2},
          ],
          ["x", "y"],
          "z",
          datatype=[self.datatype],
      )
      self.assertIsInstance(poly.data.geometry.dtype, GeometryDtype)
      roundtrip = poly.clone(datatype=["multitabular"])
      self.assertEqual(roundtrip.interface.datatype, "multitabular")
      expected = Polygons(
          [
              {
                  "x": [1, 2, 3, 1, np.nan, 6, 7, 3, 6],
                  "y": [2, 0, 7, 2, np.nan, 7, 5, 2, 7],
                  "holes": holes,
                  "z": 1,
              },
              {
                  "x": [3, 7, 6, 3, np.nan, 3, 2, 1, 3],
                  "y": [2, 5, 7, 2, np.nan, 7, 0, 2, 7],
                  "z": 2,
              },
          ],
          ["x", "y"],
          "z",
          datatype=["multitabular"],
      )
      self.assertEqual(roundtrip, expected)
  
imports: from unittest import SkipTest
  import numpy
  import pandas
  from shapely import geometry
  from holoviews.core.data import Dataset
  from holoviews.core.data.interface import DataError
  from holoviews.element import Polygons, Path, Points
  from holoviews.element.comparison import ComparisonTestCase
  from holoviews.tests.core.data.test_multiinterface import GeomTests
  from geoviews.data import GeoPandasInterface
  from .test_multigeometry import GeomInterfaceTest
label_desc: Use image node_id 6 for calling the RoundTripTests obj's underlying member method code with example usage: obj.test_multi_polygon_roundtrip() without return types