code: def unpack_data(data):
      if len(data) == 2:
          return data[0], data[1], None
      elif len(data) == 3:
          return data
      else:
          raise TypeError("Expected data to be a tuple of size 2 or 3.")
  
imports: import itertools
  import os
  import math
  import tempfile
  import pytest
  import numpy
  import tensorflow
  from tensorflow_addons.layers.crf import CRF
  from tensorflow_addons.text.crf import crf_log_likelihood
  from tensorflow_addons.utils import test_utils
label_desc: Use image node_id 5 for calling a global function with example usage: unpack_data(data) and returns: data,  data,  None, data