code: def normalize_data_format(value):
      if value is None:
          value = tf.keras.backend.image_data_format()
      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: '
              + str(value)
          )
      return data_format
  
file_path: addons/tensorflow_addons/utils/keras_utils.py
imports: import tensorflow
label_desc: Use image node_id 2 for calling a global function with example usage: normalize_data_format(value) and returns: data_format