code: def listRunSummaries(self, dataset="", run_num=-1):
          
          if run_num==-1:
              dbsExceptionHandler("dbsException-invalid-input",
                                  "The run_num parameter is mandatory",
                                  self.logger.exception)
  
          if re.search('[*,%]', dataset):
              dbsExceptionHandler("dbsException-invalid-input",
                                  "No wildcards are allowed in dataset",
                                  self.logger.exception)
          # run_num=1 caused full table scan and CERN DBS reported some of the queries ran more than 50 hours
          # We will disbale all the run_num=1 calls in DBS. Run_num=1 will be OK when dataset is given in this API.
          # YG Jan. 16 2019
          if ((run_num == -1 or run_num == '-1') and dataset==''):
              dbsExceptionHandler("dbsException-invalid-input", "Run_num=1 is not a valid input when no dataset is present.", 
                                   self.logger.exception)
          conn = None
          try:
              conn = self.dbi.connection()
              return self.dbsRunSummaryListDAO.execute(conn, dataset, run_num)
          except dbsException as de:
              dbsExceptionHandler(de.eCode, de.message, self.logger.exception, de.serverError)
          except Exception as ex:
              sError = "DBSReaderModel/listRunSummaries. %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 run summaries, like the maximal lumisection in a run.
  
          :param dataset: dataset name (Optional)
          :type dataset: str
          :param run_num: Run number (Required)
          :type run_num: str, long, int
          :rtype: list containing a dictionary with key max_lumi