code: def normalization_factor(window_size):
      exponent = 0 if window_size == 1 else 2 * window_size - 4
      return 2.0 ** (-exponent)
  
imports: from nvidia.dali.pipeline import pipeline_def
  import nvidia.dali.types
  import nvidia.dali.fn
  import numpy
  import cv2
  from scipy.ndimage import convolve1d, filters
  import os
  from nose_utils import assert_raises
  from nose.plugins.attrib import attr
  from sequences_test_utils import video_suite_helper, ArgCb
  from test_utils import get_dali_extra_path, check_batch, RandomlyShapedDataIterator
label_desc: Use image node_id 6 for calling a global function with example usage: normalization_factor(window_size) and returns: unknown