code: def train(self, mode=True):
      if mode:
          self.fail_arithmetic = False  # reset on .train()
      super().train(mode=mode)
  
file_path: gpytorch/test/likelihoods/test_noise_models.py
imports: import unittest
  import torch
  import gpytorch
  from gpytorch.likelihoods import HeteroskedasticNoise
label_desc: Use image node_id 2 for calling the NumericallyUnstableModelExample obj's underlying member method code with example usage: obj.train(mode) without return types