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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, sender, content):
 """ Calls back listener when a message is received """

        if self.handle_message is not None:
            try:
                self.handle_message(sender, content)
            except Exception as ex:
                logging.exception("Error calling message listener: %s", ex)