class CSVAggregation(DataObjectSupportingAggregation):
    """Represents a CSV Aggregation in HydroShare"""
    @classmethod
    def create(cls, base_aggr):
        return super().create(aggr_cls=cls, base_aggr=base_aggr)

    def as_data_object(self, agg_path: str) -> 'pandas.DataFrame':
        """
        Loads the CSV aggregation to a pandas DataFrame object
        :param agg_path: the path to the Time Series aggregation
        :return: the CSV aggregation as a pandas DataFrame object
        """
        if pandas is None:
            raise Exception("pandas package not found")

        return self._get_data_object(agg_path=agg_path, func=pandas.read_csv, comment="#", dtype="string",
                                     engine="python")

    def save_data_object(self, resource: 'Resource', agg_path: str, as_new_aggr: bool = False,
                         destination_path: str = "") -> 'Aggregation':

        """
        Saves the pandas DataFrame object to the CSV aggregation
        :param resource: the resource containing the aggregation
        :param agg_path: the path to the CSV aggregation
        :param as_new_aggr: Defaults False, set to True to create a new CSV aggregation
        :param destination_path: the destination path in Hydroshare to save the new aggregation
        :return: the updated or new CSV aggregation
        """
        self._validate_aggregation_for_update(resource, AggregationType.CSVFileAggregation)
        file_path = self._validate_aggregation_path(agg_path, for_save_data=True)
        self._data_object.to_csv(file_path, index=False)
        aggr_main_file_path = self.main_file_path
        data_object = self._data_object
        if not as_new_aggr:
            # cache some of the metadata fields of the original aggregation to update the metadata of the
            # updated aggregation
            keywords = self.metadata.subjects
            additional_meta = self.metadata.additional_metadata
            title = self.metadata.title

            # upload the updated aggregation files to the temp folder - to create the updated aggregation
            self._update_aggregation(resource, file_path)
            # retrieve the updated aggregation
            aggr = resource.aggregation(file__path=aggr_main_file_path)

            # update metadata
            for kw in keywords:
                if kw not in aggr.metadata.subjects:
                    aggr.metadata.subjects.append(kw)
            aggr.metadata.additional_metadata = additional_meta
            aggr.metadata.title = title
            aggr.save()
        else:
            # creating a new aggregation by uploading the updated data files
            resource.file_upload(file_path, destination_path=destination_path)

            # retrieve the new aggregation
            agg_path = urljoin(destination_path, os.path.basename(aggr_main_file_path))
            aggr = resource.aggregation(file__path=agg_path)
            data_object = None

        aggr._data_object = data_object
        return aggr