code: def get_dynamic_window_reader():
      reader = ImageReader(["image", "sampler"])
      reader.initialise(
          DYNAMIC_MOD_DATA, DYNAMIC_MOD_TASK, dynamic_list
      )
      return reader
  
imports: from __future__ import absolute_import, division, print_function
  import os
  import unittest
  import numpy
  import tensorflow
  from niftynet.engine.image_window import N_SPATIAL
  from niftynet.engine.sampler_balanced_v2 import BalancedSampler, balanced_spatial_coordinates
  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_dynamic_window_reader() and returns: reader