class_docstr: A wrapper class for testing core utils functions
code: def test_masked_whiten(self):
      whiten_unmasked = whiten(self.test_input_unmasked)
      whiten_masked = masked_whiten(self.test_input, self.test_mask)[
          1:3
      ]
      diffs = (whiten_unmasked - whiten_masked).sum()
      self.assertAlmostEqual(diffs, 0)
  
file_path: trl/tests/test_core.py
imports: import unittest
  import torch
  from trl.core import masked_mean, masked_var, masked_whiten, whiten
label_desc: Use image node_id 4 for calling the CoreTester obj's underlying member method code with example usage: obj.test_masked_whiten() without return types