code: def test_unfold(self):
      a = torch.arange(7)
  
      r = unfold(a, 3, 3, 1)
      expected = torch.tensor(
          [
              [0, 1, 2],
              [3, 4, 5],
          ]
      )
      assert_equal(r, expected)
  
      r = unfold(a, 3, 2, 1)
      expected = torch.tensor([[0, 1, 2], [2, 3, 4], [4, 5, 6]])
      assert_equal(r, expected)
  
      r = unfold(a, 3, 2, 2)
      expected = torch.tensor(
          [
              [0, 2, 4],
              [2, 4, 6],
          ]
      )
      assert_equal(r, expected)
  
file_path: vision/test/test_datasets_video_utils.py
imports: import pytest
  import torch
  from common_utils import assert_equal, get_list_of_videos
  from torchvision import io
  from torchvision.datasets.video_utils import unfold, VideoClips
label_desc: Use image node_id 1 for calling the TestVideo obj's underlying member method code with example usage: obj.test_unfold() without return types