code: def listFileParentsByLumi(self, block_name='', logical_file_name=[]):
          
          #self.logger.debug("lfn %s, block_name %s" % (logical_file_name, block_name))
          if not block_name:
              dbsExceptionHandler('dbsException-invalid-input', \
                  "Child block_name is required for fileparents/listFileParentsByLumi api", self.logger.exception )
          with self.dbi.connection() as conn:
              sqlresult = self.fileparentbylumi.execute(conn, block_name, logical_file_name)
              return [{"child_parent_id_list":sqlresult}]
docs: required parameter: block_name
          returns:  [{child_parent_id_list: [(cid1, pid1), (cid2, pid2), ... (cidn, pidn)]}]