code: def median_blur_cksize_pipe(data_src, layout, ksize):
      img = fn.external_source(
          source=data_src, batch=True, layout=layout, device="gpu"
      )
      return fn.experimental.median_blur(img, window_size=ksize)
  
file_path: DALI/dali/test/python/operator_1/test_median_blur.py
imports: import nvidia.dali
  import nvidia.dali.fn
  import cv2
  import numpy
  import multiprocessing
  import test_utils
  from nose2.tools import params
label_desc: Use image node_id 5 for calling a global function with example usage: median_blur_cksize_pipe(data_src, layout, ksize) and returns: fn