diff --git a/README.md b/README.md
index d5d98110ae11b2ad89efab9cf60ccf1d45d1e3e3..d9ed8341dd359bcd83f2662ef7fe33220ef9d859 100644
--- a/README.md
+++ b/README.md
@@ -223,7 +223,7 @@ Edit `AppDelegate.m`:
 +   [RNFIRMessaging willPresentNotification:notification withCompletionHandler:completionHandler];
 + }
 +
-+ - (void)userNotificationCenter:(UNUserNotificationCenter *)center didReceiveNotificationResponse:(UNNotificationResponse *)response withCompletionHandler:(void (^)())completionHandler
++ - (void)userNotificationCenter:(UNUserNotificationCenter *)center didReceiveNotificationResponse:(UNNotificationResponse *)response withCompletionHandler:(void (^)(void))completionHandler
 + {
 +   [RNFIRMessaging didReceiveNotificationResponse:response withCompletionHandler:completionHandler];
 + }