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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 append_records(self, dataset_key, stream_id, body):
 """Append records to a stream. :param dataset_key: Dataset identifier, in the form of owner/id :type dataset_key: str :param stream_id: Stream unique identifier. :type stream_id: str :param body: Object body :type body: obj :raises RestApiException: If a server error occurs Examples -------- """

        owner_id, dataset_id = parse_dataset_key(dataset_key)
        try:
            return self._streams_api.append_records(owner_id, dataset_id,
                                                    stream_id, body)
        except _swagger.rest.ApiException as e:
            raise RestApiError(cause=e)