Saves the provided comment to the current dataset.

        :param cellid: number of the current cell
        :type cellid: int
        :param comment: a message to add documentation to data
        :type comment: str

def set_comment(self, cellid, comment):
        """Saves the provided comment to the current dataset.

        :param cellid: number of the current cell
        :type cellid: int
        :param comment: a message to add documentation to data
        :type comment: str
        """
        info = {'cellid': cellid, 'comment': comment}
        self.datafile.set_metadata(self.current_dataset_name, info)