diff --git a/static/usage/v7/theming/automatic-dark-mode/angular/example_component_ts.md b/static/usage/v7/theming/automatic-dark-mode/angular/example_component_ts.md
index add5097b954..c2fec94b65b 100644
--- a/static/usage/v7/theming/automatic-dark-mode/angular/example_component_ts.md
+++ b/static/usage/v7/theming/automatic-dark-mode/angular/example_component_ts.md
@@ -17,7 +17,7 @@ export class ExampleComponent implements OnInit {
   }
 
   // Add or remove the "dark" class on the document body
-  toggleDarkTheme(shouldAdd) {
+  toggleDarkTheme(shouldAdd: boolean) {
     document.body.classList.toggle('dark', shouldAdd);
   }
 }