def METHOD_NAME(self, record: MutableMapping[str, Any]) -> MutableMapping[str, Any]:
    """
    Transform 'date-time' items to RFC3339 format
    """
    for item in record:
        if item in self.date_time_fields and record[item]:
            record[item] = pendulum.parse(record[item]).to_rfc3339_string()
    return record