class_docstr: Reversible Layer.
class_docstr_tok: ["Reversible","Layer","."]
code: def backward(
      self, inputs, output, grad, weights, state, new_state, rng
  ):
      del inputs
      _, inputs_weights_grad = self.reverse_and_grad(
          output, grad, weights, state, new_state, rng
      )
      return inputs_weights_grad
  
imports: from absl import logging
  import jax
  from trax import fastmath
  from trax.layers import base
  from trax.layers import combinators
label_desc: Use image node_id 5 for calling the ReversibleLayer obj's underlying member method code with example usage: obj.backward(inputs, output, grad, weights, state, new_state, rng) and returns: inputs_weights_grad