code: def test_grid_sampling():
      assert str(GridSampling(5)) == "GridSampling(size=5)"
  
      pos = torch.tensor(
          [
              [0.0, 2.0],
              [3.0, 2.0],
              [3.0, 2.0],
              [2.0, 8.0],
              [2.0, 6.0],
          ]
      )
      y = torch.tensor([0, 1, 1, 2, 2])
      batch = torch.tensor([0, 0, 0, 0, 0])
  
      data = Data(pos=pos, y=y, batch=batch)
      data = GridSampling(size=5, start=0)(data)
      assert len(data) == 3
      assert data.pos.tolist() == [[2, 2], [2, 7]]
      assert data.y.tolist() == [1, 2]
      assert data.batch.tolist() == [0, 0]
  
imports: import torch
  from torch_geometric.data import Data
  from torch_geometric.testing import withPackage
  from torch_geometric.transforms import GridSampling
label_desc: Use image node_id 1 for calling a global function with example usage: test_grid_sampling() without return types