code: def medialaxis(image, multichannel, volumetric):
      if multichannel:
          image = rgb_to_greyscale(image)
  
      if volumetric:
          data = numpy.zeros_like(image)
  
          for z, plane in enumerate(image):
              data[z] = medial_axis(plane)
          return data
      else:
          return medial_axis(image)
  
label_desc: Use image node_id 1 for calling a global function with example usage: medialaxis(image, multichannel, volumetric) and returns: data, medial_axis