code: def donut():
      
      import numpy as np
      segmentation = np.zeros([20, 30, 40])
      # generate test data
      segmentation[6:10, 7:24, 10:37] = 1
      segmentation[6:10, 7, 10] = 0
      segmentation[6:10, 23, 10] = 0
      segmentation[6:10, 7, 36] = 0
      segmentation[6:10, 23, 36] = 0
      segmentation[2:18, 12:19, 18:28] = 2
  
      data3d = segmentation * 100 + np.random.random(segmentation.shape) * 30
      voxelsize_mm=[3,2,1]
  
      datap = {
          'data3d': data3d,
          'segmentation': segmentation.astype(np.int8),
          'voxelsize_mm': voxelsize_mm,
          "slab": {"donut": 1, "stick": 2}
      }
      # io3d.write(datap, "donut.pklz")
      return datap
docs: Generate donut like shape with stick inside
  
      :return: datap with keys data3d, segmentation and voxelsize_mm