code: def test_ignore_index_label_smoothing_cross_entropy(self):
      config = {
          "name": "label_smoothing_cross_entropy",
          "ignore_index": -1,
          "smoothing_param": 0.2,
      }
      crit = LabelSmoothingCrossEntropyLoss.from_config(config)
      outputs = torch.tensor([[0.0, 7.0]])
      targets = torch.tensor([[-1]])
      self.assertAlmostEqual(crit(outputs, targets).item(), 3.50090909)
  
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 9 for calling the TestLabelSmoothingCrossEntropyLoss obj's underlying member method code with example usage: obj.test_ignore_index_label_smoothing_cross_entropy() without return types