diff --git a/go.mod b/go.mod
index 81357de..e6b04d1 100644
--- a/go.mod
+++ b/go.mod
@@ -11,5 +11,6 @@ require (
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.11.0 // indirect
 	golang.org/x/sys v0.4.0 // indirect
 )
diff --git a/internal/exercises/templates/16_range_built_in/range_built_in.go b/internal/exercises/templates/16_range_built_in/range_built_in.go
index 2ba423a..89a8271 100644
--- a/internal/exercises/templates/16_range_built_in/range_built_in.go
+++ b/internal/exercises/templates/16_range_built_in/range_built_in.go
@@ -10,7 +10,7 @@ func sumSlice(s []int) int {
 
 func countMap(m map[string]int) int {
 	count := 0
-	for range m {
+	for _, _ = range m {
 		count++
 	}
 	return count