diff --git a/README.md b/README.md
index 3a64397..4aa97b3 100644
--- a/README.md
+++ b/README.md
@@ -150,6 +150,7 @@ The function passed to `.Call()` must take
 
 - `*ga.Service` used to call home assistant services
 - `*ga.State` used to retrieve state from home assistant
+- `ga.EventData` containing the event data that triggered the listener
 
 ```go
 func myFunc(se *ga.Service, st *ga.State) {