old_contents: # Tai Sakuma <tai.sakuma@gmail.com>
  
  ##__________________________________________________________________||
  class NullProgressMonitor(object):
      def createReporter(self): return None
      def begin(self): pass
      def end(self): pass
  
  ##__________________________________________________________________||
  
new_contents: # Tai Sakuma <tai.sakuma@gmail.com>
  
  ##__________________________________________________________________||
  class NullProgressMonitor(object):
      def __repr__(self):
          return '{}()'.format(self.__class__.__name__)
  
      def createReporter(self): return None
      def begin(self): pass
      def end(self): pass
  
  ##__________________________________________________________________||
  
subject: add __repr__()