code: def get_3d_reader():
      """
      define the 3d reader
      :return: 3d reader
      """
      reader = ImageReader(["image"])
      reader.initialise(MULTI_MOD_DATA, MULTI_MOD_TASK, multi_mod_list)
      return reader
  
imports: from __future__ import absolute_import, division, print_function
  import os
  import nibabel
  import tensorflow
  import pandas
  import numpy
  from niftynet.engine.sampler_resize_v2 import ResizeSampler
  from niftynet.engine.windows_aggregator_identity import WindowAsImageAggregator
  from niftynet.io.image_reader import ImageReader
  from niftynet.io.image_sets_partitioner import ImageSetsPartitioner
  from niftynet.layer.discrete_label_normalisation import DiscreteLabelNormalisationLayer
  from niftynet.layer.pad import PadLayer
  from niftynet.utilities.util_common import ParserNamespace
  from tests.niftynet_testcase import NiftyNetTestCase
label_desc: Use image node_id 1 for calling a global function with example usage: get_3d_reader() and returns: reader