diff --git a/lib/cpp/src/concurrency/Mutex.h b/lib/cpp/src/concurrency/Mutex.h
index d4788b3..7945e05 100644
--- a/lib/cpp/src/concurrency/Mutex.h
+++ b/lib/cpp/src/concurrency/Mutex.h
@@ -48,7 +48,7 @@
   impl* impl_;
 };
 
-class Guard{
+class Guard {
  public: 
   Guard(const Mutex& value) : mutex_(value) {
     mutex_.lock();