code: def listDataTiers(self, data_tier_name=""):
          
          data_tier_name = data_tier_name.replace("*", "%")
  
          try:
              conn = self.dbi.connection()
              return self.dbsDataTierListDAO.execute(conn, data_tier_name.upper())
          except dbsException as de:
              dbsExceptionHandler(de.eCode, de.message, self.logger.exception, de.message)
          except ValueError as ve:
              dbsExceptionHandler("dbsException-invalid-input2", "Invalid Input Data",  self.logger.exception, ve.message)
          except TypeError as te:
              dbsExceptionHandler("dbsException-invalid-input2", "Invalid Input DataType",  self.logger.exception, te.message)
          except NameError as ne:
              dbsExceptionHandler("dbsException-invalid-input2", "Invalid Input Searching Key",  self.logger.exception, ne.message)
          except Exception as ex:
              sError = "DBSReaderModel/listDataTiers. %s\n. Exception trace: \n %s" \
                      % ( ex, traceback.format_exc())
              dbsExceptionHandler('dbsException-server-error',  dbsExceptionCode['dbsException-server-error'], self.logger.exception, sError)
          finally:
              if conn:
                  conn.close()
docs: API to list data tiers known to DBS.
  
          :param data_tier_name: List details on that data tier (Optional)
          :type data_tier_name: str
          :returns: List of dictionaries containing the following keys (data_tier_id, data_tier_name, create_by, creation_date)