code: def adafactor_decay_rate_adam(beta2):
      """Second-moment decay rate like Adam, subsuming the correction factor.
  
      Args:
        beta2: a float between 0 and 1
      Returns:
        a scalar
      """
      t = (
          tf.cast(tf.train.get_or_create_global_step(), tf.float32)
          + 1.0
      )
      decay = (
          beta2
          * (1.0 - tf.pow(beta2, t - 1.0))
          / (1.0 - tf.pow(beta2, t))
      )
      return decay
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import functools
  import re
  import gin
  from mesh_tensorflow import layers
  from mesh_tensorflow import ops_with_redefined_builtins
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling a global function with example usage: adafactor_decay_rate_adam(beta2) and returns: decay