code: def run(self):
          '''Run the callback periodically'''
          while not self.wait(self.delay()):
              try:
                  logger.info('Invoking callback %s', self.callback)
                  self.callback()
              except StandardError:
                  logger.exception('Callback failed'f run(self):
          '''Run the callback periodically'''
          while not self.wait(self.delay()):
              try:
                  logger.info('Invoking callback %s', self.callback)
                  self.callback()
              except StandardError:
                  logger.exception('Callback failed')
docs: Run the callback periodically