code: def normalize_data_format(value):
      data_format = value.lower()
      if data_format not in {"channels_first", "channels_last"}:
          raise ValueError(
              "The `data_format` argument must be one of "
              '"channels_first", "channels_last". Received: '
              f"{str(value)}."
          )
      return data_format
  
imports: import tensorflow.compat.v2
  from tensorflow_probability.python import random
  from tensorflow_probability.python.distributions import independent
  from tensorflow_probability.python.distributions import kullback_leibler
  from tensorflow_probability.python.distributions import normal
  from tensorflow_probability.python.internal import docstring_util
  from tensorflow_probability.python.internal import tf_keras
  from tensorflow_probability.python.layers import util
  from tensorflow_probability.python.util.seed_stream import SeedStream
  from tensorflow.python.ops import nn_ops
label_desc: Use image node_id 3 for calling a global function with example usage: normalize_data_format(value) and returns: data_format