code: def _load(self, exit_on_failure):
          
          # pylint: disable-msg=W0621
          log = logging.getLogger('argtoolbox')
          discoveredFileList = []
          if self.config_file:
              if isinstance(self.config_file, types.UnicodeType):
                  discoveredFileList = self.file_parser.read(self.config_file)
              else:
                  discoveredFileList = self.file_parser.readfp(
                      self.config_file,
                      "file descriptor")
          else:
              defaultFileList = []
              defaultFileList.append(self.prog_name + ".cfg")
              defaultFileList.append(
                  os.path.expanduser('~/.' + self.prog_name + '.cfg'))
              defaultFileList.append('/etc/' + self.prog_name + '.cfg')
              log.debug("defaultFileList: " + str(defaultFileList))
              discoveredFileList = self.file_parser.read(defaultFileList)
  
          log.debug("discoveredFileList: " + str(discoveredFileList))
  
          if self.mandatory and len(discoveredFileList) < 1:
              msg = "The required config file was missing."
              msg += " Default config files : " + str(defaultFileList)
              log.error(msg)
              raise EnvironmentError(msg)
  
          log.debug("loading configuration ...")
          if exit_on_failure:
              for s in self.sections.values():
                  log.debug("loading section : " + s.get_section_name())
                  try:
                      s.load(self.file_parser)
                  except ValueError:
                      sys.exit(1)
          else:
              for s in self.sections.values():
                  log.debug("loading section : " + s.get_section_name())
                  s.load(self.file_parser)
  
          log.debug("configuration loaded.")
docs: One you have added all your configuration data (Section, Element,
          ...) you need to load data from the config file.