docs: def _update(self, archive_name, version_metadata):
          '''
          Updates the version specific metadata attribute in DynamoDB
          In DynamoDB this is simply a list append on this attribute value
  
          Parameters
          ----------
          archive_name: str
              unique '_id' primary key
  
          version_metadata: dict
              dictionary of version metadata values
  
          Returns
          -------
          dict
              list of dictionaries of version_history
          '''
  
          command = "SET version_history = list_append(version_history, :v)"
  
          self._table.update_item(
              Key={'_id': archive_name},
              UpdateExpression=command,
              ExpressionAttributeValues={':v': [version_metadata]},
              ReturnValues='ALL_NEW')