code: def test_nans(self, input_data):
      [seg_1, seg_2, spacing] = input_data
      seg_1 = torch.tensor(seg_1)
      seg_2 = torch.tensor(seg_2)
      sur_metric = SurfaceDistanceMetric(
          include_background=False, get_not_nans=True
      )
      # test list of channel-first Tensor
      batch_seg_1 = [seg_1.unsqueeze(0)]
      batch_seg_2 = [seg_2.unsqueeze(0)]
      sur_metric(batch_seg_1, batch_seg_2, spacing=spacing)
      result, not_nans = sur_metric.aggregate(reduction="mean")
      np.testing.assert_allclose(0, result, rtol=1e-5)
      np.testing.assert_allclose(0, not_nans, rtol=1e-5)
  
file_path: MONAI/tests/test_surface_distance.py
imports: from __future__ import annotations
  import unittest
  import numpy
  import torch
  from parameterized import parameterized
  from monai.metrics import SurfaceDistanceMetric
label_desc: Use image node_id 2 for calling the TestAllSurfaceMetrics obj's underlying member method code with example usage: obj.test_nans(input_data) without return types