diff --git a/cal_tools/cal_tools/ana_tools.py b/cal_tools/cal_tools/ana_tools.py
index c4399fb9dd8f8dc6f1516d388fb0b77f17a028e4..804a16b42b6db00cc6dbf9ea0dc47d64c0a488b1 100644
--- a/cal_tools/cal_tools/ana_tools.py
+++ b/cal_tools/cal_tools/ana_tools.py
@@ -170,7 +170,7 @@ def combine_lists(*args, names=None):
     for param in params:
         possible_params = [x + [y] for x in possible_params for y in param]
 
-    if names:
+    if isinstance(names, list) and len(names)==len(args):
         d_possible_params = []
         for par in possible_params:
             d_possible_params.append(dict(zip(names, par)))