message: Use MEAN_IDX and VAR_IDX in _NormalizingCombiner
diff: @@ -330,8 +330,8 @@ class _NormalizingCombiner(base_preprocessing_layer.Combiner):
  """Convert an accumulator into a dict of output values."""
  return {
  _COUNT_NAME: accumulator[self.COUNT_IDX],
  - _MEAN_NAME: accumulator[1],
  - _VARIANCE_NAME: accumulator[2]
  + _MEAN_NAME: accumulator[self.MEAN_IDX],
  + _VARIANCE_NAME: accumulator[self.VAR_IDX]
  }
  def restore(self, output):
  @@ -354,8 +354,8 @@ class _NormalizingCombiner(base_preprocessing_layer.Combiner):
  """Serialize an accumulator for a remote call."""
  output_dict = {
  _COUNT_NAME: accumulator[self.COUNT_IDX].tolist(),
  - _MEAN_NAME: accumulator[1].tolist(),
  - _VARIANCE_NAME: accumulator[2].tolist()
  + _MEAN_NAME: accumulator[self.MEAN_IDX].tolist(),
  + _VARIANCE_NAME: accumulator[self.VAR_IDX].tolist()
  }
  return compat.as_bytes(json.dumps(output_dict))
  