text: import torch
  import torchio as tio
  from ...utils import TorchioTestCase
  
  
  class TestContour(TorchioTestCase):
      """Tests for `Contour`."""
      def test_one_hot(self):
          image = self.sample_subject.label
          tio.Contour()(image)
  
      def test_multichannel(self):
          label_map = tio.LabelMap(tensor=torch.rand(2, 3, 3, 3) > 1)
          with self.assertRaises(RuntimeError):
              tio.Contour()(label_map)
  