code: def test_running_mean(self):
      x = np.random.uniform(size=10)
      state = normalization.running_mean_init(shape=())
      for i in range(len(x)):
          state = normalization.running_mean_update(x[i], state)
          np.testing.assert_almost_equal(
              normalization.running_mean_get_mean(state),
              np.mean(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 1 for calling the NormalizationTest obj's underlying member method code with example usage: obj.test_running_mean() without return types