code: def _build_logging_config(level, apps_list, verbose, filename=None):
      
      config = copy.deepcopy(DEFAULT_LOGGING)
  
      # Swap out default stream handler for a file handler, if
      # a filename is given
      if filename:
          config['handlers']['default'].update(
              {
                  'class': 'logging.handlers.WatchedFileHandler',
                  'filename': filename,
              }
          )
  
      if verbose:
          config['handlers']['default']['formatter'] = 'verbose'
  
      config['loggers'] = build_app_loggers(level, apps_list)
  
      return config
docs: Return a copy of the DEFAULT_LOGGING config with installed application
      loggers at the given log level.  The 'default' handler is kept as a
      console/stream writer unless a filename is passed in, which swaps the stream
      handler out for a file handler.  The 'verbose' formatter is used if
      verbosity is enabled.