code: def get_2d_reader():
      mod_2d_list = data_partitioner.initialise(
          MOD_2D_DATA
      ).get_file_list()
      reader = ImageReader(["image"])
      reader.initialise(MOD_2D_DATA, MOD_2D_TASK, mod_2d_list)
      return reader
  
file_path: NiftyNet/niftynet/contrib/segmentation_selective_sampler/test_sampler_selective.py
imports: from __future__ import absolute_import, division, print_function
  import os
  import numpy
  import tensorflow
  from niftynet.contrib.segmentation_selective_sampler.sampler_selective import SelectiveSampler, Constraint
  from niftynet.io.image_reader import ImageReader
  from niftynet.io.image_sets_partitioner import ImageSetsPartitioner
  from niftynet.utilities.util_common import ParserNamespace
  from tests.niftynet_testcase import NiftyNetTestCase
label_desc: Use image node_id 3 for calling a global function with example usage: get_2d_reader() and returns: reader