diff --git a/src/core/widgets/key.py b/src/core/widgets/key.py
index 046edf5..b1776cb 100644
--- a/src/core/widgets/key.py
+++ b/src/core/widgets/key.py
@@ -69,4 +69,4 @@ class Key(Gtk.Button or Gtk.ToggleButton):
         if not self.iscontrol:
             self._is_upper = not self._is_upper
             if not self._is_symbol:
-                self.set_label(self._primary_symbol.upper()) if self._is_upper else self.set_label(self._primary_symbol.lower())
+                self.set_label(self._primary_symbol.upper()) if self._is_upper else self.set_label(self._primary_symbol.lower())
\ No newline at end of file