diff --git a/src/main/java/org/cqfn/astranaut/core/algorithms/DeepTraversal.java b/src/main/java/org/cqfn/astranaut/core/algorithms/DeepTraversal.java
index ae79d69..f24d99f 100644
--- a/src/main/java/org/cqfn/astranaut/core/algorithms/DeepTraversal.java
+++ b/src/main/java/org/cqfn/astranaut/core/algorithms/DeepTraversal.java
@@ -25,6 +25,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 import org.cqfn.astranaut.core.Node;
 
 /**
@@ -54,10 +55,10 @@ public DeepTraversal(final Node root) {
      * And yes, you can use this algorithm not only to find nodes, but also just to traverse
      * the tree in the specific order.
      * @param visitor Visitor that processes nodes
-     * @return Found node or {@code null} if no node is found
+     * @return Found node (optional)
      */
-    public Node findFirst(final Visitor visitor) {
-        return DeepTraversal.findFirst(this.root, visitor);
+    public Optional<Node> findFirst(final Visitor visitor) {
+        return Optional.ofNullable(DeepTraversal.findFirst(this.root, visitor));
     }
 
     /**
diff --git a/src/test/java/org/cqfn/astranaut/core/algorithms/DeepTraversalTest.java b/src/test/java/org/cqfn/astranaut/core/algorithms/DeepTraversalTest.java
index a2a6a19..3b76c48 100644
--- a/src/test/java/org/cqfn/astranaut/core/algorithms/DeepTraversalTest.java
+++ b/src/test/java/org/cqfn/astranaut/core/algorithms/DeepTraversalTest.java
@@ -24,6 +24,7 @@
 package org.cqfn.astranaut.core.algorithms;
 
 import java.util.List;
+import java.util.Optional;
 import org.cqfn.astranaut.core.DraftNode;
 import org.cqfn.astranaut.core.Node;
 import org.junit.jupiter.api.Assertions;
@@ -39,17 +40,17 @@ class DeepTraversalTest {
     void testFindFirst() {
         final Node root = DraftNode.createByDescription("A(B,C,D(E<\"eee\">,F<\"fff\">)))");
         final DeepTraversal traversal = new DeepTraversal(root);
-        final Node node = traversal.findFirst(node1 -> !node1.getData().isEmpty());
-        Assertions.assertNotNull(node);
-        Assertions.assertEquals("E", node.getTypeName());
+        final Optional<Node> node = traversal.findFirst(node1 -> !node1.getData().isEmpty());
+        Assertions.assertTrue(node.isPresent());
+        Assertions.assertEquals("E", node.get().getTypeName());
     }
 
     @Test
     void testNotFoundFirst() {
         final Node root = DraftNode.createByDescription("A(B,C,D)");
         final DeepTraversal traversal = new DeepTraversal(root);
-        final Node node = traversal.findFirst(node1 -> !node1.getData().isEmpty());
-        Assertions.assertNull(node);
+        final Optional<Node> node = traversal.findFirst(node1 -> !node1.getData().isEmpty());
+        Assertions.assertFalse(node.isPresent());
     }
 
     @Test