code: def create_callback_with_list_comprehension_referencing_global_var():
      def get_data(sample_info):
          return [
              x
              for xs in [
                  [
                      np.fromfile(jpeg_file, dtype=np.uint8)
                      for _ in range(sequence_lenght)
                  ]
                  for i in range(2)
              ]
              for x in xs
          ]
  
      return get_data
  
imports: import copyreg
  import numpy
  import nvidia.dali.fn
  import nvidia.dali.pickling
  import os
  from nvidia.dali import pipeline_def
  from pickle import PicklingError
  from nose_utils import raises
  from test_utils import get_dali_extra_path, restrict_python_version
label_desc: Use image node_id 16 for calling a global function with example usage: create_callback_with_list_comprehension_referencing_global_var() and returns: get_data, unknown