class_docstr: Layer normalization.
class_docstr_tok: ["Layer","normalization","."]
code: def init_weights_and_state(self, input_signature):
      features = input_signature.shape[-1]
      scale = jnp.ones(features, dtype=input_signature.dtype)
      bias = jnp.zeros(features, dtype=input_signature.dtype)
      self.weights = scale, bias
  
imports: from trax.fastmath import numpy
  from trax.layers import base
label_desc: Use image node_id 3 for calling the LayerNorm obj's underlying member method code with example usage: obj.init_weights_and_state(input_signature) without return types