code: def test_simple_ivw(self) -> None:
      means = np.array([1, 2, 3])
      variances = np.array([1, 1, 1])
      new_mean, new_var = inverse_variance_weight(means, variances)
      self.assertEqual(new_mean, 2.0)
      self.assertEqual(new_var, 1 / 3)
  
imports: from itertools import product
  import numpy
  import pandas
  from ax.core.data import Data
  from ax.utils.common.testutils import TestCase
  from ax.utils.stats.statstools import inverse_variance_weight, marginal_effects, relativize, relativize_data, unrelativize
label_desc: Use image node_id 3 for calling the InverseVarianceWeightingTest obj's underlying member method code with example usage: obj.test_simple_ivw() without return types