new_contents: import tensorflow as tf
  
  from .util import funcname_scope, static_rank, dimension_indices
  from .variable import variable
  
  
  
  @funcname_scope
  def layer_normalization(x: ("batch", ...)):
    assert static_rank(x) >= 2
    return (x - _batchwise_mean(x)) / _stddev(x) * variable([], "stddev")
  
  
  @funcname_scope
  def _batchwise_mean(x):
    return tf.reduce_mean(x, dimension_indices(x, 1), keep_dims=True)
  
  
  @funcname_scope
  def _stddev(x):
    return tf.sqrt(tf.reduce_sum(tf.square(x - _batchwise_mean(x)),
                                 dimension_indices(x, 1),
                                 keep_dims=True))
  
subject: Add normalization.layer_normalization()