code: def format(self, record):
          
  
          record_fields = record.__dict__.copy()
          self._set_exc_info(record_fields)
  
          event_name = 'default'
          if record_fields.get('event_name'):
              event_name = record_fields.pop('event_name')
  
          log_level = 'INFO'
          if record_fields.get('log_level'):
              log_level = record_fields.pop('log_level')
  
          [record_fields.pop(k) for k in record_fields.keys()
           if k not in self.fields]
  
          defaults = self.defaults.copy()
          fields = self.fields.copy()
          fields.update(record_fields)
          filtered_fields = {}
          for k, v in fields.iteritems():
              if v is not None:
                  filtered_fields[k] = v
  
          defaults.update({
              'event_timestamp': self._get_now(),
              'event_name': event_name,
              'log_level': log_level,
              'fields': filtered_fields})
  
          return json.dumps(defaults, default=self.json_default)
docs: formats a logging.Record into a standard json log entry
  
          :param record: record to be formatted
          :type record: logging.Record
          :return: the formatted json string
          :rtype: string