code: def test_quantize(self):
      data_random = Data(
          pos=torch.randn(100, 3) * 0.1, x=torch.ones((100, 1))
      )
      gr = cT.GridSampling3D(0.2, quantize_coords=True)
      quantized = gr(data_random)
      self.assertTrue(hasattr(quantized, "coords"))
      self.assertEqual(quantized.x.shape[0], quantized.coords.shape[0])
      self.assertEqual(quantized.num_nodes, quantized.coords.shape[0])
      self.assertEqual(quantized.coords.dtype, torch.int)
  
file_path: torch-points3d/test/test_grid_sampling.py
imports: import os
  import sys
  import numpy
  import torch
  import unittest
  import h5py
  import numpy.testing
  import numpy.matlib
  from torch_geometric.data import Data
  import torch_points3d.core.data_transform
label_desc: Use image node_id 5 for calling the TestGridSampling3D obj's underlying member method code with example usage: obj.test_quantize() without return types