code: def _select_decay_fn(key):
      if key == configs.DecayType.EXPONENTIAL_DECAY:
          return tf.compat.v1.train.exponential_decay
      elif key == configs.DecayType.INVERSE_TIME_DECAY:
          return tf.compat.v1.train.inverse_time_decay
      elif key == configs.DecayType.NATURAL_EXP_DECAY:
          return tf.compat.v1.train.natural_exp_decay
      else:
          raise ValueError("Invalid configs.DecayType %s." % key)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import neural_structured_learning.configs
  import six
  import tensorflow
label_desc: Use image node_id 10 for calling a global function with example usage: _select_decay_fn(key) and returns: tf, tf, tf