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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def __notify(self):
 """ Notify the given callback about the result of the execution """

        if self.__callback is not None:
            try:
                self.__callback(
                    self._done_event.data,
                    self._done_event.exception,
                    self.__extra,
                )
            except Exception as ex:
                self._logger.exception("Error calling back method: %s", ex)