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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 a log record to JSON, if the message is a dict assume an empty message and use the dict as additional fields. """


        fields = record.__dict__.copy()

        if isinstance(record.msg, dict):
            fields.update(record.msg)
            fields.pop('msg')
            msg = ""
        else:
            msg = record.getMessage()

        try:
            msg = msg.format(**fields)
        except (KeyError, IndexError, ValueError):
            pass
        except:
            # in case we can not format the msg properly we log it as is instead of crashing
            msg = msg

        if 'msg' in fields:
            fields.pop('msg')

        if 'exc_info' in fields:
            if fields['exc_info']:
                formatted = tb.format_exception(*fields['exc_info'])
                fields['exception'] = formatted
            fields.pop('exc_info')

        if 'exc_text' in fields and not fields['exc_text']:
            fields.pop('exc_text')

        logr = self.defaults.copy()

        logr.update({'@message': msg,
                     '@timestamp': datetime.datetime.utcnow().strftime('%Y-%m-%dT%H:%M:%S.%fZ'),
                     '@source_host': self.source_host,
                     '@fields': self._build_fields(logr, fields)})

        return json.dumps(logr, default=self.json_default, cls=self.json_cls)