diff --git a/armi/reactor/parameters/parameterCollections.py b/armi/reactor/parameters/parameterCollections.py
index f0db55369..10eee345b 100644
--- a/armi/reactor/parameters/parameterCollections.py
+++ b/armi/reactor/parameters/parameterCollections.py
@@ -497,7 +497,7 @@ def restoreBackup(self, paramsToApply):
     def where(
         self, f: Callable[[parameterDefinitions.Parameter], bool]
     ) -> Iterator[parameterDefinitions.Parameter]:
-        """Produce an iterator over parameters that meet some criteria
+        """Produce an iterator over parameters that meet some criteria.
 
         Parameters
         ----------