diff --git a/.github/workflows/codecov.yml b/.github/workflows/codecov.yml
index 97c4813..a8f932c 100644
--- a/.github/workflows/codecov.yml
+++ b/.github/workflows/codecov.yml
@@ -18,13 +18,13 @@ jobs:
     steps:
 
       - name: Set up Go 1.21
-        uses: actions/setup-go@v1
+        uses: actions/setup-go@v5
         with:
           go-version: '1.21'
         id: go
 
       - name: Check out code into the Go module directory
-        uses: actions/checkout@v1
+        uses: actions/checkout@v4
 
       - name: Get dependencies
         run: |
diff --git a/.github/workflows/goci.yml b/.github/workflows/goci.yml
index 7f575a8..ec4de54 100644
--- a/.github/workflows/goci.yml
+++ b/.github/workflows/goci.yml
@@ -16,10 +16,10 @@ jobs:
     name: run
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Set up Go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version: '1.21'
 
diff --git a/.github/workflows/golangci-lint.yml b/.github/workflows/golangci-lint.yml
index 5e7579d..4d913fb 100644
--- a/.github/workflows/golangci-lint.yml
+++ b/.github/workflows/golangci-lint.yml
@@ -15,11 +15,11 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/setup-go@v4
+      - uses: actions/setup-go@v5
         with:
           go-version: '1.21'
           cache: false
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3
         with:
diff --git a/cmd/main.go b/cmd/main.go
index ce23826..149d125 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -27,9 +27,9 @@ func main() {
 	fmt.Println(ok)             // true
 	fmt.Println(root.GetData()) // 0.0
 
-	node, ok := tr.Get(3)
-	fmt.Println(ok)             // true
-	fmt.Println(node.GetData()) // 1.3
+	found, ok := tr.Get(3)
+	fmt.Println(ok)              // true
+	fmt.Println(found.GetData()) // 1.3
 
 	structure, ok := tr.GetStructure()
 	fmt.Println(ok)        // true
@@ -37,7 +37,7 @@ func main() {
 
 	nodes, ok := tr.Backtrack(6)
 	fmt.Println(ok) // true
-	for _, node := range nodes {
-		fmt.Println(node.GetData()) // 2.6; 0.2; 0.0
+	for _, n := range nodes {
+		fmt.Println(n.GetData()) // 2.6; 0.2; 0.0
 	}
 }