code: def get_3d_reader():
      data_param = {
          "mr": {
              "path_to_search": IMAGE_PATH_3D,
              "filename_contains": "FLAIR",
              "interp_order": 1,
          }
      }
      reader = ImageReader().initialise(data_param)
      return reader
  
imports: from __future__ import absolute_import, print_function
  import os
  import numpy
  import tensorflow
  from niftynet.engine.image_window_dataset import ImageWindowDataset
  from niftynet.io.image_reader import ImageReader
  from tests.niftynet_testcase import NiftyNetTestCase
label_desc: Use image node_id 2 for calling a global function with example usage: get_3d_reader() and returns: reader