diff -r c36e549a7f12 -r c3e95212e3f0 config.py
--- a/config.py	Sun Jan 21 00:58:06 2018 +0000
+++ b/config.py	Sun Jan 21 01:14:06 2018 +0000
@@ -119,7 +119,7 @@
 logging.info("Reading configuration file %s" % cfgfile)
 
 if not (os.path.exists(cfgfile) and os.path.isfile(cfgfile)):
-    raise SystemExit(f'Configuration file required: {cfgfile}')
+    raise SystemExit('Configuration file required: {cfgfile}')
 
 with io.open(cfgfile, 'r') as file:
     settings=expand_env(yaml.load(file), os.environ);