diff --git a/src/cal_tools/calcat_interface2.py b/src/cal_tools/calcat_interface2.py
index e5e1bc26711cd58f06c8654abfcd60ec6ab6b3a6..464ff85c576b69ef4a7a7435f9a9cfe48b76fc95 100644
--- a/src/cal_tools/calcat_interface2.py
+++ b/src/cal_tools/calcat_interface2.py
@@ -756,7 +756,7 @@ class CalibrationData(Mapping):
             modules = self.qm_names
         else:
             raise ValueError(
-                f"{module_naming=} (must be 'aggregator', 'modnum' or 'qm'"
+                f"{module_naming=} (must be 'aggregator', 'modnum' or 'qm')"
             )
 
         cal_groups = [
@@ -766,7 +766,7 @@ class CalibrationData(Mapping):
         tables = []
         # Loop over groups of calibrations.
         for cal_group in cal_groups:
-            table = ["Modules"] + cal_group
+            table = [["Modules"] + cal_group]
 
             # Loop over calibrations and modules to form the next rows.
             for mod in modules:
@@ -790,7 +790,7 @@ class CalibrationData(Mapping):
                         except KeyError:
                             mod_consts.append(f"{c_time} ({singleconst.ccv_id})")
 
-                table.append([mod] + mod_consts)
+                table.append([str(mod)] + mod_consts)
 
             tables.append(table)