code: def set_comment(self, cellid, comment):
          
          info = {'cellid': cellid, 'comment': comment}
          self.datafile.set_metadata(self.current_dataset_name, info)
docs: 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