class_docstr: This class consists of network variables and operations at each iteration.
  It is generated by the application engine but can be modified by the
  application as well.
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docstr: Engine check this property after each iteration
  
  This could be modified in by application
  ``application.set_iteration_update()``
  to create training schedules such as early stopping.
  
  :return: None or a handler that requested to stop the loop
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code: def should_stop(self):
      """
      Engine check this property after each iteration
  
      This could be modified in by application
      ``application.set_iteration_update()``
      to create training schedules such as early stopping.
  
      :return: None or a handler that requested to stop the loop
      """
      return self._should_stop
  
imports: import itertools
  import time
  from niftynet.engine.application_variables import CONSOLE, TF_SUMMARIES
  from niftynet.engine.signal import TRAIN, VALID, INFER
  from niftynet.utilities.util_common import look_up_operations
label_desc: Use image node_id 9 for calling the IterationMessage obj's underlying member method code with example usage: obj.should_stop() and returns: self