code: def test_running_variance(self):
      x = np.random.uniform(size=10)
      state = normalization.running_mean_and_variance_init(shape=())
      for i in range(len(x)):
          state = normalization.running_mean_and_variance_update(
              x[i], state
          )
          np.testing.assert_almost_equal(
              normalization.running_mean_and_variance_get_variance(
                  state
              ),
              np.var(x[: i + 1]),
          )
  
file_path: trax/trax/rl/normalization_test.py
imports: from absl.testing import absltest
  import numpy
  from trax import shapes
  from trax.rl import normalization
label_desc: Use image node_id 2 for calling the NormalizationTest obj's underlying member method code with example usage: obj.test_running_variance() without return types