class_docstr: Crop a patch from a 3D image from 'start' of patch size.
  The patch size should be less than the image size.
  
  :param start start point list[depth, height, width] for cropping
  :param patchSize patch size list[depth, height, width]
code: def __init__(self, start, patch_size, bigdl_type="float"):
      super(Crop3D, self).__init__(bigdl_type, start, patch_size)
  
imports: import sys
  import numpy
  from bigdl.util.common import *
  from zoo.feature.image.imagePreprocessing import *
  from zoo.feature.image.imageset import *
label_desc: Use image node_id 1 to create a new Crop3D object from inherited base classes: ImagePreprocessing3D with example: obj = Crop3D(start, patch_size, bigdl_type)