code: def ref_func(img, ksize, layout):
      ksize = ksize[0]
      dst = np.zeros_like(img)
      if layout[0] == "F":
          for f in range(0, img.shape[0]):
              cv2_median_blur(
                  dst[f, :, :, :], img[f, :, :, :], ksize, layout
              )
      else:
          cv2_median_blur(dst, img, ksize, layout)
      return dst
  
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 2 for calling a global function with example usage: ref_func(img, ksize, layout) and returns: dst