docs: def read_configuration_files(self):
          '''Explicitly read the configuration files.
  
          Reads all configuration files in this Parameters object.  Even if
          inotify is watching or a read has already occurred.
  
          .. note::
  
             The order that the configuration files are read is not guaranteed.
  
          '''
  
          for file_name, configuration_parser in self.configuration_files.items():
              if os.access(file_name, os.R_OK):
                  configuration_parser.read(file_name)
              else:
                  logger.warn('could not read %s', file_name)
                  warnings.warn('could not read {}'.format(file_name), ResourceWarning)