code: def listPrimaryDSTypes(self, primary_ds_type="", dataset=""):
          
          conn = self.dbi.connection()
          try:
              result = self.primdstypeList.execute(conn, primary_ds_type, dataset)
              if conn: conn.close()
              return result
          finally:
              if conn:
                  conn.close()
docs: Returns all primary dataset types if dataset or primary_ds_type are not passed.