diff --git a/README.md b/README.md
index f015edf..0a43ebc 100644
--- a/README.md
+++ b/README.md
@@ -218,8 +218,15 @@ import (
 	"fmt"
 	"github.com/showwin/speedtest-go/speedtest"
 	"github.com/showwin/speedtest-go/speedtest/transport"
+	"log"
 )
 
+func checkError(err error) {
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
 // Note: The current packet loss analyzer does not support udp over http.
 // This means we cannot get packet loss through a proxy.
 func main() {