diff --git a/soitool/modules/module_base.py b/soitool/modules/module_base.py
index c9f6a266e6fac6759bac07577b3768b3007a08c6..568c9fa952e7893592117732af26a9c7922d5f55 100644
--- a/soitool/modules/module_base.py
+++ b/soitool/modules/module_base.py
@@ -155,7 +155,7 @@ def event_is_ctrl_plus(event):
     Returns
     -------
     bool
-        True if is event is 'CTRL +'
+        True if event is 'CTRL +'.
     """
     return (
         event.modifiers() == Qt.ControlModifier and event.key() == Qt.Key_Plus