code: def test_metric_normalization_factor(
      self, expected_norm_factor, atol
  ):
      norm_factor = self.space.metric.normalization_factor(
          self.model.variances
      )
      self.assertAllClose(norm_factor, expected_norm_factor, atol=atol)
  
file_path: geomstats/geomstats/test_cases/learning/expectation_maximization.py
imports: import pytest
  import geomstats.backend
  from geomstats.test.test_case import TestCase
  from geomstats.test_cases.learning._base import BaseEstimatorTestCase
label_desc: Use image node_id 3 for calling the GaussianMixtureModelTestCase obj's underlying member method code with example usage: obj.test_metric_normalization_factor(expected_norm_factor, atol) without return types