Properly separate line choices

monitor.py

@@ -96,7 +96,7 @@ try:
     if cfg['crawl']['station_id'] is not None:
         USE_STATION_ID = cfg['crawl'].getint('station_id')
     else:
-        sys.exit(f"Please specify a station_id in the [crawl] section of {args.config}")
+        sys.exit('Please specify a station_id in the [crawl] section of {}'.format(args.config))
     USE_LINES = cfg['crawl']['use_lines'].split(',')
 except (IndexError, configparser.NoOptionError, configparser.NoSectionError):
     sys.exit("There is something wrong with the configuration file. Exiting.")