diff --git a/nipap-cli/helper-nipap b/nipap-cli/helper-nipap
index 7081a9002..f9f759783 100755
--- a/nipap-cli/helper-nipap
+++ b/nipap-cli/helper-nipap
@@ -28,7 +28,7 @@ if __name__ == '__main__':
     userrcfile = os.path.expanduser('~/.nipaprc')
 
     # read configuration
-    cfg = configparser.ConfigParser({'prefix_list_columns': None })
+    cfg = configparser.ConfigParser({'prefix_list_columns': ''})
     cfg.read(userrcfile)
     nipap_cli.cfg = cfg