diff --git a/Rx.playground/Pages/Transforming_Observables.xcplaygroundpage/Contents.swift b/Rx.playground/Pages/Transforming_Observables.xcplaygroundpage/Contents.swift
index 1b7e776c..92fcff8e 100644
--- a/Rx.playground/Pages/Transforming_Observables.xcplaygroundpage/Contents.swift
+++ b/Rx.playground/Pages/Transforming_Observables.xcplaygroundpage/Contents.swift
@@ -44,8 +44,9 @@ example("flatMap") {
     let sequenceString = Observable.of("A", "B", "C", "D", "E", "F", "--")
 
     _ = sequenceInt
-        .flatMap { int in
-            sequenceString
+        .flatMap { (x:Int) -> Observable<String> in
+            print("from sequenceInt \(x)")
+            return sequenceString
         }
         .subscribe {
             print($0)