diff --git a/notebooks/Jungfrau/Jungfrau_Gain_Correct_and_Verify_NBC.ipynb b/notebooks/Jungfrau/Jungfrau_Gain_Correct_and_Verify_NBC.ipynb
index f8d83b318ec5d5666871dc225d4dc103dfc33960..18c8c93290cab3f29cacf73e018753331a7b206d 100644
--- a/notebooks/Jungfrau/Jungfrau_Gain_Correct_and_Verify_NBC.ipynb
+++ b/notebooks/Jungfrau/Jungfrau_Gain_Correct_and_Verify_NBC.ipynb
@@ -274,7 +274,7 @@
     "    from datetime import datetime\n",
     "\n",
     "    jungfrau_consts = jungfrau_cal_mdata(gm=1)\n",
-    "    if not jungfrau_consts.aggregator_names:\n",
+    "    if not jungfrau_consts:\n",
     "        warning(\n",
     "            \"No fixed gain offset constants found. \"\n",
     "            \"Looking for dynamic gain constant.\"\n",
diff --git a/src/cal_tools/calcat_interface2.py b/src/cal_tools/calcat_interface2.py
index 07f141d64064f7a06aa170a5fd11a13b7598941a..f22b745f9d56d23a784de63953941f0af4bb92ad 100644
--- a/src/cal_tools/calcat_interface2.py
+++ b/src/cal_tools/calcat_interface2.py
@@ -692,6 +692,10 @@ class CalibrationData(Mapping):
     def __len__(self):
         return len(self.constant_groups)
 
+    def __bool__(self):
+        # Do we have any constants of any type?
+        return any(bool(grp) for grp in self.constant_groups.values())
+
     def __contains__(self, item):
         return item in self.constant_groups