Fix another dict iteration

src/cal_tools/calcat_interface2.py

@@ -77,7 +77,7 @@ class ModulesConstantVersions:
     constants: Dict[str, SingleConstantVersion]  # Keys e.g. 'LPD00'
 
     def select_modules(self, *aggregators) -> "ModulesConstantVersions":
-        d = {aggr: scv for (aggr, scv) in self.constants if aggr in aggregators}
+        d = {aggr: scv for (aggr, scv) in self.constants.items() if aggr in aggregators}
         return ModulesConstantVersions(d)
 
     @property