code: def test_build_label_smoothing_cross_entropy(self):
      config = {
          "name": "label_smoothing_cross_entropy",
          "ignore_index": -1,
          "smoothing_param": 0.1,
      }
      crit = build_loss(config)
      self.assertTrue(isinstance(crit, LabelSmoothingCrossEntropyLoss))
      self.assertEqual(crit._ignore_index, -1)
  
file_path: ClassyVision/test/losses_label_smoothing_cross_entropy_loss_test.py
imports: import copy
  import unittest
  import torch
  from classy_vision.losses import build_loss, LabelSmoothingCrossEntropyLoss
label_desc: Use image node_id 1 for calling the TestLabelSmoothingCrossEntropyLoss obj's underlying member method code with example usage: obj.test_build_label_smoothing_cross_entropy() without return types