diff --git a/example/go.mod b/example/go.mod
index 5986060..7036633 100644
--- a/example/go.mod
+++ b/example/go.mod
@@ -1,3 +1,5 @@
 module github.com/antonmashko/envconf/example
 
 go 1.21.0
+
+require github.com/antonmashko/envconf v1.4.6
diff --git a/example/go.sum b/example/go.sum
new file mode 100644
index 0000000..637ba73
--- /dev/null
+++ b/example/go.sum
@@ -0,0 +1,2 @@
+github.com/antonmashko/envconf v1.4.6 h1:u2h1Zmrgrf501Zc7mXGENR5YA0JwM7JE63AVYabgmXM=
+github.com/antonmashko/envconf v1.4.6/go.mod h1:8tLk5O33IWWcVlFCjN8xMCZ9u8d58cWwVejEKYIXxi0=
diff --git a/example/main.go b/example/main.go
index 23591bd..034f9b0 100644
--- a/example/main.go
+++ b/example/main.go
@@ -27,7 +27,6 @@ type Example struct {
 func main() {
 	var cfg Example
 	err := envconf.Parse(&cfg,
-		option.WithExternal(&json.Json{}),
 		option.WithLog(log.Default()),
 		option.WithFlagConfigFile("config", "./conf.json", "", func(b []byte) (external.External, error) {
 			return json.Json(b), nil