diff --git a/src/xfel_calibrate/nb_args.py b/src/xfel_calibrate/nb_args.py
index edf893e003450370d1010fc81f8f9062246df19e..bdf4a7d5e7ab7bb7e5ce62c9011ffa38ceed274f 100644
--- a/src/xfel_calibrate/nb_args.py
+++ b/src/xfel_calibrate/nb_args.py
@@ -423,7 +423,7 @@ def parse_argv_and_load_nb(argv) -> Tuple[Dict, NBDetails]:
               'location is sufficient for your '
               'needs.'.format(', '.join(not_reproducible_args)))
 
-        if not args['not_reproducible']:
+        if not args.not_reproducible:
             # If not explicitly specified that reproducibility may be
             # broken, remind the user and exit.
             print('To proceed, you can explicitly allow reproducibility to '