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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 format(self, record):
 """Format the message into JSON expected by fluentd. :type record: :class:`~logging.LogRecord` :param record: the log record :rtype: str :returns: A JSON string formatted for GKE fluentd. """

        message = super(ContainerEngineHandler, self).format(record)
        return format_stackdriver_json(record, message)